Very nice, job Random_Taffer. Took me 2.5 hours, and I found a good bit of the loot.
I've got one very MINOR issue to report. No doubt you may have seen this in testing.
spoiler:
The first time I stepped into the Night Masks' hideout, the speech from the guy behind the window and my own reply to it overlapped in portions; that is, you could hear us both speaking simultaneously. Nevertheless, after the thief finished speaking, I still got all the correct items and objectives ticked off.
Again, not a major issue but I thought I'd bring it up.
Another (good) thing. I did a few things "out of order" so to say, but the game logic didn't break. Great job!
Example:
spoiler:
After I found the night masks' hideout and accepted their invitation (like I had a choice!!!

), I only noticed that I had received the sewer key, NOT the accompanying note!
So instead of reading the note and getting the corresponding objectives, I just went straight to the sewers. I ended up getting all the loot and BJing the thieves (who I later found out were Red Scorps.). I then found the hermit who gave me the entry for the gambling/social club. Now I had THOUGHT that this was the plot-advancer but of course, it just ended up being a place to find more loot. However, it did give me a reason to browse my inventory and notice the other note I had overlooked. So I read that and everything else became clear.
Anyway, my point is that I was able to back-track, get the things I needed, and then come back to the sewers and finish things there. None of the logic "broke" because I had already been to the hideout and interacted with the thieves without having objectives for such.
So kudos to your beta testers and your scripting!