In my ongoing series of "small stuff no one asked for," something that others have been looking for, too! While playing, I found the lack of any method of removal of Pain in the Necklace's Misc quest (other than killing Fethis Alor, of course) to be a bit annoying. I went looking, and found Anduniel's East Empire Pendant Quest Markers, the__mash's Map Markers for Pain in the Necklace, and Elephant42's edit/combo of the two of them in Anduniel's comments, all of which are driving in the direction I was looking for, but didn't quite get everything wrapped up. It seemed like a nice little thing to teach myself some quest work/script work, so I gave it a try.

This mod would not be possible without their efforts, I ABSOLUTELY built on top of theirs, so click through, download, and toss 'em an endorsement and a thanks for not only their work, but the open permissions :)

Details

This mod has a series of changes:

• East Empire Company Strongboxes are reverted to vanilla and no longer respawn (they technically contain one less gem to prevent folks from accidentally cleaning them as it would otherwise be an ITM).
• While they are locked and the quest is active, there are map markers pointing to the lock boxes.
• Payout of the pendants is reduced from 500 Septims to 100 (you've got a map marker now, so the effort is significantly reduced).
• The quest keeps track of how many you have sold to Fethis Athor and updates you on your progress
• Once you've sold all 33, the quest completes and is no longer active. If you have some mod-added ones, you can continue selling them, but once you've sold 33, the map markers go away.
• Fethis Athor might have a few small additions to his house upon quest completion
• Correspondingly, the next time his merchant inventory refreshes (2 days), he should have some additional inventory
• Plugin is flagged as ESL, so should not count against your load order.
  

This is my first time messing around with quests, so please let me know if you see anything wrong.
Installation
Use a mod manager/organizer to install, or drop the loose files into you Skyrim data folder. Given this involves some quests, if you've been to Raven Rock before, it probably requires a new save.

Compatibility
Not compatible with anything which touches the same quest (Pain in the Necklace). Potential incompatibility with anything that deals with containers, and/or forwards USSEP changes on containers. The original quest was intended to be repeatable (hence its Misc status), and USSEP fixes the bug where the containers do not respawn. This intentionally reverts that change to vanilla, but many other mods are out there that deal with loot/scarcity/etc which will carry forward USSEP's change. Make sure it's lower in your load order than those other mods. Other USSEP changes (the lock to the Retching Netch's strongbox, some of Athis's inventory) have been forwarded without forced master. Similarly, anything which impacts Athis's chest (LOTD, some world loot mods, etc) could probably use a bashed patch. Finally, anything which adds additional East Empire Pendants can theoretically be used to complete the quest, as well.

Credits
Bethesda for Skyrim Special Edition and the Creation Kit
ElminsterAU for SSEEdit
the__mash for Map Markers for Pain in the Necklace
Anduniel for East Empire Pendant Quest Markers
Elephant42 for his/her/their combo of the above two mods
Teabag86 for the idea of the end-of-quest merchant reward
Jampion in the Skyrim Modding Hub discord server for helping me out with a papyrus function