I don't have VR to test so i can't guarantee that everything works properly, but people say it works.
There was an issue with MCM getting stuck on Skyrim Unbound after the start but it should be fixed now.
It was reported that VR Keyboard and SkyUILib VR Patch are required to use the Save Preset option, since without them you can't type in the Save Preset text input window (which uses SkyUILib).

Yes, because SUR doesn't include any SKSE plugins. Make sure that you use the correct version of SKSE for your game version, though.

No, you guys ain't got no SKSE and SkyUI, which are hard requirements for this mod.

No.

It's relatively safe if you completed the main quest up to The Way of the Voice and joined any side of Civil War. Otherwise, no.

No, they now have huge differences so it's not safe and can cause bugs.

I don't really know what's safe or unsafe. It's better not to update anything on an actual playthrough anyway. If you're a risky guy and love danger, you can update but not to versions to which i put "New game is required when updating" or something like that into the file description on the Files tab, these versions will likely cause issues when updating midgame. It's also recommended not to keep saves created before the start created on older versions, better start a completely new game instead, because starting options that were changed in the update may work incorrectly after updating.

No, it would require compacting FormIDs, but some FormIDs are referenced in the edited vanilla scripts.

Yes, change the Dragonborn option on the first page of the MCM.

No (no, i don't plan to add it).

To get no weapons, uncheck Random and don't enable any weapons (all must be set to Nothing).
To get no armor, set Armor Type to Nothing.
To get no items, set Wealth to Nothing. (some other mods can add their items at the start, though).

You can't start it if you're non-dragonborn - Frea never appears at Miraak Temple and the cultists never come for you.

At the beginning of the game they are nowhere to be found, but during The Jagged Crown quest you encounter one of them (depending on the side you choose) as usual, except that he won't say that he knows you.

With SUR, Durhneviir won't be resurrected if you can't learn shouts.

Instead of the completion of the Dragon Rising quest, The Whispering Door now requires your relationship rank with Balgruuf to be >= 2. You can gain it by completing the prerequisite quest/quests for the Whiterun thane quest that are set in the MCM.

Most mods can be set up at any time and don't care if your character is completely created or whatever. Some mods require your character to be completely created since changing race resets some things, it should be safe to set up them in the starting room after you close the character creation menu for the last time. Though such mods usually prevent you from enabling them until the required conditions aren't met.

Note that it's recommended not to keep saves created before the start on older versions and start a completely new game when you update SUR instead, to avoid possible issues with the game start, so better use MCM Recorder, Setting Loaders and MCM presets where you can instead of creating one save with all the mods set up and using it your whole life.

SUR hides those mod messages displayed at the left top corner of the screen at the game start about mods being installed successfully. Hides, but not pauses, and then enables them back when teleporting you to the starting room. This is done on purpose.
Multiple users asked this question because they were used to wait until these messages end, as they thought that these messages mean that their mods are still actively loading and therefore it's unsafe to start the game until these messages are over. Some even were checking that each individual message is in its place.

The short answer: you don't really need to wait until these messages end or check if all the messages are on their place.


So what those messages are for and why i don't need them?

Usually those messages are called by a script after this script initialized everything, i.e. finished all operations that this mod needs to do via a script when a new game is started or the mod is loaded for the first time on an existing saved game. Or the message can also be called when the mod only starts initializing.
The purpose of these messages are usually not to let the user know when the mod is fully loaded and ready, but to let the user know that the mod "works".
In fact, in 99% cases it only means that the OnInit() script event in this specific script that calls this message is received and finished running. It doesn't guarantee that everything initialized correctly. It doesn't guarantee that all parts of the mod work. It doesn't guarantee that there are no conflicts and that none of the parts of the mod are overwritten by other mods.
Basically the only thing these messages guarantee is that the .esp of the mod is activated. And that's pretty much what these messages are for - if the user comes to the author and complains that the mod doesn't work, the author can ask the user if they see this message, to ensure that the user has the .esp of the mod activated.
Of course you want to make sure that all your mods are activated, but instead of carefully reading all those messages and ticking boxes in your notebook for each mod that should display a message, just check the list of mods and .esp plugins in your mod manager once. Also, avoid putting .esp-s before their master plugins, since that would lead to the plugin being not loaded in the game (modern mod managers, such as the latest version of Mod Organizer, ensure that automatically).
Or it's also possible that the author simply forgot or didn't care enough to remove a message that they used when creating and testing the mod.

So the facts are:
1) These messages are useless
2) It's hard to track them and a certain number of first messages will be missed by the user anyway, because the intro titles that play when you start a new game with the vanilla start or Skyrim Unbound overlap those messages.
3) Only some mods display those messages:
- Not all mods have scripts and most mod authors won't create a script just to display a message at the game start.
- Many mod authors don't consider this kind of messages to be useful and therefore they don't add any messages even if the mod has scripts with some initialization process.
4) These messages are just a bad practice:
- At the start of the game the screen gets spammed with those messages. On big load orders there may be dozens of messages that take a few minutes to stop appearing.
- They may confuse users, making them think that they need to wait until the messages stop appearing or even check if each individual message is on its place. This would kill any fun when starting a new game and you would probably do anything to avoid doing it.

It's possible that some mod displays an error or warning during loading as a message at the left top screen corner. But that's a bad idea. Not only this error/warning will be easy to miss among the dozens of other messages, but also if the mod loads fast enough the user just won't see the message because of the intro titles. The correct way to show this kind of information to the user is a MessageBox - a square window with text displayed at the center of the screen with either just an "OK" button that closes this window or more buttons. Use a messagebox and the user won't miss it.


Okay, but if these messages are still appearing, doesn't it mean that the mods aren't fully loaded yet or that there are plenty of scripts running and therefore i should wait?

Not really.

1) These messages are displayed a lot later than the mods ask the game to display them. This happens due to how these messages at the left top screen corner work. There's a constant small number of the messages on the screen, and it's not because only that number of mods can be loading at the same time (this is not true), but because the number of messages is limited to that count. The time each message is displayed for is fixed and same for all messages. It works as a queue - new messages wait for the previous ones to be displayed for the required time. Let's say you have 1000 mods that display 100 messages. Even if all mods get fully initialized and ready and ask the game to show their messages in 1 second, the messages will still slowly appear and disappear until all 100 messages won't be shown, and it would require the same time for the messages to end as if those mods initialized in 10 seconds, 30 seconds or a minute.

2) The message queue itself doesn't cause any script load, doesn't decrease your FPS or anything. It's just a part of the game UI that works not on Papyrus.

3) The fact that messages stopped to appear doesn't mean that all mods are initialized. If some mod takes a lot of time to initialize or just stucks in an endless loop, you won't know that, because these messages don't tell you "100% loaded" or something when all mods are initialized.

4) Mods actually don't take that much time to get fully initialized and ready. The Skyrim scripting language Papyrus is quite slow but not that slow. Most mods are fully initialized in a few seconds, only some take significant time. Also, they start initializing not when the first loading screen ends, but when it starts. The intro titles that play when you start a new game with Skyrim Unbound also give your mods more time to initialize.

5) Mods continue to initialize during the game start process. When you go to the Skyrim Unbound MCM or any other MCM, the mods that haven't initialized yet will continue to initialize in the background, the message queue isn't paused when you're in an MCM. While you're being teleported to the starting room, creating your character in RaceMenu, staying in the starting room, the few mods that haven't initialized yet also continue to initialize. At the moment you're teleported to your starting location all your mods will likely already be initialized.

6) Nothing bad will happen if you continue the game start process while some scripts are still running. The game is able to handle many scripts running at the same time, without this your 1000 mods wouldn't be able to initialize correctly at the same time when you start a new game. Using the SUR MCM and continuing the game start is just another script running. The worst that can happen - SUR may work slower, but nothing will break.

7) Even if some mods are not fully initialized yet after the game start, it's usually not a problem. You're not using all of the features of all of your mods the moment you start a new game.


So when is it safe to go to the SUR MCM and start the game?

If you don't have a lot of mods, you can do it as quick as you can.
If you have hundreds or thousands of mods, most likely nothing bad will happen if you do the same. But if you want to give your mods more time to load:
1) If you setup the SUR MCM or create your character from scratch, you can do everything right away. This will give your mods enough time to initialize before you're teleported to your starting location.
2) You can disable the "Short Intro Titles" and "Quick Start" global options if you have them enabled. This will give your mods more time to load before you're even able to do anything.

Data\SKSE\Plugins\SkyrimUnbound\Presets (If you use Mod Organizer, see this directory in your overwrite folder)

A .json configuration file SKSE\Plugins\SkyrimUnbound\SkyrimUnboundBalance.json allows to change the balance of randomization such as random counts of items. It's only used if PapyrusUtil is installed and working. You can open it via any text editor including Windows Notepad and edit the values.

"bounty" : [ 250, 2500, 60 ]
This is the default auto bounty. The first value is min bounty, the second one is max bounty, the third one is the chance of a bounty in percents, i.e. the default settings given you a bounty between 250 and 2500 septims with 60% chance.

All other values control the randomization of starting items and follow the same logic:

• Each item group has 4 lines in the config, which represent the Wealth set selected by the player or randomly. 1 = Beggar, 2 = Poor, 3 = Medium, 4 =  Wealthy. Potions are an exception, since they're disabled for the Beggar set.
• Each line contains an array of 2 or 3 values. The 1st one is the minimum number of items, the 2nd one is the maximum number of items, the 3rd one is the minimum number of items when that item is set to Enabled in the MCM by the player (SUR increases the minimum number in this case to better meet the player expectations).
• The third one is optional and can be removed if you don't want to increase the number of items when these items are set to Enabled.
  

Spell addons are in Data\SKSE\Plugins\SkyrimUnbound\Addons\. To remove an addon, delete its file from this folder or remove the contents of the file. The order of the addons can be changed by renaming their files (in any way you want).

See Creating Addons for Skyrim Unbound Reborn.

If you need to run something after the character creation, you can check if the player controls are enabled. An example is my Choose Your Starting Skills. It will be triggered after the teleportation If you select "Continue", or after you click "Stay here". This method won't require any dependency on Skyrim Unbound.

You can also check the stage of SkyrimUnbound quest. In addition to stages 10 and 100, i added 20, 30, 90 in Skyrim Unbound Reborn:
10 - Skyrim Unbound is started, the player isn't teleported to the starting room yet (except the QuickStart mode);
20 - the player is teleported to the starting room, the character creation menu will be opened soon;
30 - the player selected Stay Here after the character creation and stays in the starting room (skipped otherwise);
90 - the player leaves the starting room, the fade-out plays;
100 - the player is teleported to the starting location, the controls are enabled.
To avoid adding Skyrim Unbound as a master, you can use Game.GetFormFromFile() papyrus function.

Alternatively, you can check if the player is in HelgenLocation: both Helgen and the starting room have it set as location. This method is NOT recommended for mod-added menus that pop up on game start, since SUR can't control this to delay these me

There are also SKSE Mod Events available:
SkyrimUnbound_OnAddonsLoaded
SkyrimUnbound_OnItemsAdded - called every time starting items are given.
SkyrimUnbound_OnPlayerTeleported - called when the player is teleported to the starting location.
SkyrimUnbound_OnAdventureBegun - called after the player is teleported to the starting location when all necessary preparations after it are done.
SkyrimUnbound_OnControlsEnabled - sent: 1) after Stay Here. 2) same as OnAdventureBegun if the player didn't choose Stay Here.
SkyrimUnbound_OnControlsEnabledAfterRaceMenu - sent: 1) after Stay Here. 2) if the player has choosen Stay Here, each time the player closes racemenu after choosing Open RaceMenu option from the actions in the starting room. 3) same as OnAdventureBegun if the player didn't choose Stay Here.
For mod-added menus that pop up on game start i recommend the last three and don't recommend OnPlayerTeleported.
Usage example:

See Patching conditions for Skyrim Unbound.

I don't plan it.

I don't plan it