Thanks for playing the game! Glad you like it and sorry you got stuck.
In the upcoming update (v1.1) I improve a few of the quest issues people were having. It’s hard to tell exactly the issue here, but to get the quest from the creature in the cells you need to finish the Olivia statue quest and Shrine quest (one by spider queen). I think once those are done and you go back to the door you get the quest to activate (unless it’s already on there) That might be what is holding you back? If you already did those and still stuck let me know. If needed I can send you the early access link on Disc as a fix. I’m not 100% I got all the bugs and hate to hear when people hit them.
The Fawn quest still showing seems like a bug and I’ll have to look into it. It’s the first bug report I got on that one.
If you didn’t know already, there is a cheat menu in the bookshelf to unlock the gallery if you felt you missed anything. Or if you wait for the update it, might fix your issue.