This is a simple conversion of Dudestia's NPC Clothes Changer and Maintainer. The mod from LE works fine in SE so feel free to dowload that one instead, if you prefer. The only difference is that this version has the Form 43 changed to 44 to avoid the warning by mod managers, the item limit is raised from the previous 10 items per NPC and the slot limit has been upped from 200 to 500 according to Dudestia's tutorial.

All the credit goes to dudestia for creating this amazing mod which has worked flawlessly for me and others for years.

Link to Dudestia's original LE version

Permissions are open on the original mod, in case anyone was wondering :)

And huge thanks to CyborgArmGun for creating a script to solve the 10-item limit on NPCs. 

Feel free to share your screenshots of the outfits you made the NPCs wear :) Just keep it SFW so that I don't have to change the tags ;)


How it works

This system is completely separate and standalone and it doesn't affect NPC dialogue. That's why you don't need to disable any follower framework mods for this to work. It works alongside any of them (AFT, NFF, etc.) But it's always a good idea to keep it one outfit manager per NPC (meaning if you try to use both managers on one NPC, I can't guarantee no wonkiness and strange stuff)

Once you have the mod enabled, you should recieve a ring into your inventory named "Ring of Fashion Designer". If this ring is equipped, any friendly NPC that you talk to will first display a window of options.
To do the basic dress-up, all you need to do is:
1. give the NPC the items you want them to wear
2. close the inventory (the NPC will equip the items automatically
3. lock the outfit
To change the outfit, you need to have it unlocked for the process. To stop controlling their outfits altogether, you need to release them.
Detailed explanations:

• Dress Up/Change Dress - you may give the NPC items to wear. Simply put the items into their inventory upon choosing this option, they will equip them automatically. Thanks to CyborgArmGun, a script is included which removes the previous limitation of the NPCs only being able to wear 10 items at once. It has been tested with up to 22 items at once and it worked perfectly. I'm not sure what the actual limit is now, but rest assured, there's more than enough clothing/armor slots to fill for each of the 500 NPCs ;)
• Lock/unlock - lock the outfit to keep it on the NPC even after you change a cell or reload. Unlock to undo this. Note that locking the outfit will prevent the NPC from wearing any other things that they recieve from you further, you need to unlock them to change the outfit again and then lock them again so that they keep wearing that outfit :)
• Remove Default - remove their default outfit permanently. This is useful for when an NPC wears something you don't want them to wear nor do you want to replace it with anything (helmet, gloves, etc. More info in Troubleshooting). While this change is permanent, it does not carry across saves.
• Release - remove the NPC from the ring's slots and let the game handle their outfits again. This is the equivalent of undoing all the shenanigans that you have been doing with the NPC's outfits :D Beware that if you've removed their default outfit before, they may end up naked. You can try the 'resurrect' console command to fix that, but I can't guarantee that it will work.
• Talk to NPC - this one is pretty self-explanatory :D You get to proceed as you would normally without the ring.
  

To talk to NPCs without the options window popping up, simply unequip the ring ;)

Please note that there is an item in Hearthfires DLC and mods such as Prince and Pauper that is called 'Child's clothes'. These are not clothes. They cannot be equipped in any way by a child. It's a miscellaneous item and therefore not equippable. You can only dress children in the same clothes that you would dress other NPCs in.



Pro tip!  - Don't like an NPC's hair and don't want to download a large NPC overhaul? You can change their hair by equipping them with any wig with the use of the ring :)
If you want to change their haircolor too, you can use wig mods that involve color options, such as KS Hair Wigs (LE version, but the non-hdt works in SE without conversion). For the colors to appear properly, however, you would have to make these changes to RaceMenu:

Installation

Just install whichever version you like with your choice of a mod manager. Only one of them is necessary, all the required filles are included in both. There's really nothing more to it :)


Uninstalling

Uninstalling this mod mid-playthrough should be completely safe. If you want to be extra careful, make a save somewhere with no altered NPCs around and then unistall.
One thing that will likely happen though is that anyone who had their outfit changed by this mod will be naked once it is removed. There's a simple solution to this by opening up the console (with the tilde key), clicking on each affected NPC and doing a 'resurrect' command on each one of them. Beware that this fix might not work on those who had their outfits removed, but you should try anyway, maybe you'll get lucky.


ESL-flagged version

I have looked into making this an ESL-flagged plugin and it seems to be working well, but I have not tested this very extensively. It should be working fine though, I don't see why it wouldn't :)
There is no need to remove the esp version if you wish to switch to the ESL-flagged one. Just replace it with the ESL-flagged one and even all the outfits should remain in place without any hassle :)


Troubleshooting

I am not a modder. I have merely converted this. I will attempt to help with any problems, but be aware that my knowledge of scripts and CK is very limited. But there's a few issues I can think of for now, at least.

No ring added to inventory
If the ring somehow doesn't end up in your inventory, either add it with AddItemMenu, or you can open the console with the tilde key ( ` )  and type in:
help "ring of fashion"
A code will be displayed that should be different for each of you, but it will end with the same three characters (D64). Next, type in this without the brackets:
player.additem [the code] 1
This should add the ring into your inventory :)

Weapon sheathe/draw animation is glitching
A glitch can occasionally occur if the outfits are locked with the draw/sheathe weapon animations for the NPCs. They get stuck looping in the animation rapidly and cannot finish it. It seems random to me, so I can't pinpoint the actual cause for now, but there is a very simple fix. When they get stuck in this animation, just unlock them and once the animation finishes, lock them again :) (you don't even need to wait for them to finish combat. You can just quickly do it right away). They should be fine after that :)

Two outfits are glitching through on an NPC
Sometimes, when you lock an NPC who is quest-related and scripted to change armor during a questline (such as Delphine, Brynjolf or Karliah), they will glitch out when they try to change the outfit. This will result in their outfits flickering one through another. There's a simple fix to this. Either you can unlock or release them before this outfit change happens, but even if you're past that, it's not the end of the world ;) You can unlock or release them after and re-enter the cell. This should fix them. Or you can always remove their default outfit after the change and give them whatever you wish again.

NPC retains gear in unfilled slots and you don't want it there
If an NPC has a clothing slot filled (such as helmet) and you equip them with dress only, the helmet will obviously remain equipped until you replace it. The same goes for any slot which you yourself do not replace (boots, gauntlests, etc.). To get rid of these items, if you don't want to replace them, you can't just fill the slot and then remove the new item again, because the old item will reappear eventually. You need to either use the Remove Default fuction to remove everything from the NPC and only equip them with the things that you want to wear, or you can use console commands 'showinventory' and 'removeitem [code] [count]' to get rid of these things for good. Removing the default outfit is the easier option.

When equipping children, they end up naked instead
I personally suspect that this is an issue with vanilla children only and that the various children replacers out there solve this. But in any case, whatever the cause is, this mod should resolve the issue for you Armor and Clothing for Kids.


Outfits in the screenshots

Elisif - red Noble Dress, circlet and necklace from Newmiller's Drake2, earrings from Newmiller's jewelry, hair with veil from Apachii Divine Elegance, ruby ring from Real Engagement Rings (LE version, works in SE) and Solitude signet ring from DovahBling Jewelry (LE only, needs to be converted with Cathedral Asset Optimizer)

Bryling - Gold Jaquard dress from Kozakowy's Black Corset Dress, gothic gloves from Apachii Divine Elegance, gold bracelets and earrings from DovahBling Jewelry (viz Elisif), circlet from Elleh's Circlet Replacer (LE version works in SE), necklace from Elven Sniper 4

Mila - red Opulent Maid Dress, ribbon from Wa Ribbons, neck beads from Newmiller's jewelry

Bolgeir - armor from The Breton Paladin, circlet from KD circlets

Una - maid outfit from Osare Maid Outfit (LE version, needs to be converted with Cathedral Asset Optimizer, SE converted version availible for CBBE but only in black)

Random guard - armor from Regal Paladin Armor, headband from KD circlets

Erikur - lord armor with collar from Apachii Divine Elegance

Falk - clothes from Ashara Romantic Outfit with Royal Retexture (LE retexture works on SE outfit), vanilla amulet retexture from DovahBling Jewelry (viz Elisif)

Argonian added by Dawn of Skyrim - armor from Glowing Ebony Armor

Dead guard - Radovid armor and accessories from Apachii Divine Elegance

Camilla - red Ashara Imperial Outfit, necklace and earrings from Leah Lilith Jewelry (LE version works in SE, file only availible on LoversLab, but there's no NSFW content in it), rings and bracelets from DovahBling Jewelry (viz Elisif)