I'm currently experiencing the "This Person is Busy" bug in the following 5 unrelated quests:

(Sorry the quest names probably aren't correct, but you get the idea!)

Repairing The White Phial (Return to Quintus Navale)
Quintus Navale shows the dialog option about having all of the items to repair the Phial, he then goes about repairing the Phial and watching his master die, though I cannot talk to him - permanently. It says "This person is busy" from the time I give him the ingredients to the time when he's standing over his dead master, and that message never goes away.

I've read that it can be solved using the console to set quest stage, but that's absolutly not true for me, unless I'm just doing it wrong. I've had multiple attempts at advancing this quest's stage to 100 via "setstage MS12b 100", but I just get a message that the quest is completed. I get no reward, no phial, and it still says "This person is busy" on Quintus Navale - permanently. I've tried exiting and entering the building at several different spots during the animation of him repairing the Phial and talking to his master. I've tried staying downstairs for a while or instead following him upstairs immediately. Nothing works.

Attend Your Wedding Ceremony
The priest is permanently busy after my bride says "I do". Leaving the building causes me to fail the quest. I think waiting in place did too, if I remember correctly.

Join the Thieves Guild
I follow the guy into the main guild area for the first time to speak with the guildmaster. After a short conversation between them, I'm apparently supposed to speak to the master directly but both guys are permanently busy. Leaving, waiting or fighting does not fix the problem.

Stormcloaks - Free Solitude
After killing the commander, Ulfric and the other guy are permanently busy and I can't continue the quest. Leaving, waiting or fighting does not fix the problem.

Repair Azura's Star
When I give the star to the elf in the tavern so he can repair it, it shows a short animation and he says "it needs more souls", or something like that, then he is busy permanently like the others. Leaving and fighting do not fix the problem. I didn't even bother "waiting".

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All of these problems occur for me now within the same save file, for the same character. I'm at level 50-something.

Current version: 1.6.89.0.6
(According to the Esc screen)

I've also had the 1.6 beta and all other previous patches, including all betas before it.

Current mods:
HighResTexturePack01.esp
HighResTexturePack02.esp
Auto Unequip Arrows
Stones of Barenziah Quest Markers
Better Quest Objectives
Frostfall (most recent mod - I installed it after experiencing 4 of the 5 issues mentioned previously.)
Realistic Ragdolls and Force
Dwemer Certified (already disabled before experiencing 1 or 2 new issues, mentioned previously.)
Elvenwood
Imp's More Complex Needs
Same Walk & run Speeds (Lite) (I'm pretty sure this was installed after experiencing 1 or 2 of the issues.)
Skyrim Speeds (installed same time as previous mod)
ScenicCarriage
Sounds of Skyrim - The Dungeons (I'm pretty sure this was installed after experiencing 1 or 2 of the issues.)
Sounds of Skyrim - The Wilds (installed same time as previous mod)

I tried disabling all of my mods (expect the official HD texture packs) and then reloaded from an earlier save, far from the tavern in which the elf repairs Azura's star, without having entered the tavern yet. Then I rode a horse to the tavern and entered it for the "first" time. However, the problem still exists - the elf is still labeled as "This Person is Busy" after the animation plays and he says "it needs more souls".

So does this mean that none of the mods are at fault? Or is my current save file somehow corrupted permanently even after I disable all of my mods?

Thanks for any help.

I should probably add that I've played through 2 characters already. This is my 3rd. I don't recall ever having this problem with either of my previous 2 characters. With my first character, I probably played over 95% of all available quests, including the random quest "types".

Though I didn't play the Stormcloaks questline with either my first or second characters - I remained neutral with both. My 3rd character is the first time I'm doing the Stoarmcloaks questline.

Also, I don't recall if I had used any mods for my first character, though maybe 1 or 2. I'm pretty sure I used a couple of mods for my second character.

My 3rd character is the first to use Imp's More Complex Needs mod, since level 1 if I remember correctly. I had also enabled a fixed timescale with the recommended minimum value: 5. I'm sure I played for many levels before running into the "This Person is Busy" issue, which started with "Reparinig the White Phial", which leads me to believe that this mod isn't related to the issue.

I'd be happy to send a copy of my latest save file to Bethesda if it would help.

Thanks.