Hello there and thank you for doing this thread, I was about to make one of my own and ask about some of the stuff you've written here as well as how hard you guys think it will be to get 100% on this? I tried Hell difficulty today because you noted that it'll be needed for the game to give you the high-level gear and I feel it's very hard alone since you can get swamped by enemy fire suddenly. I tried the classic save scumming trick and thankfully it worked since without that I don't see a way to ever get 100% on this due to the random nature of what enemies spawn when you load a game or enter a room. Just like you said, there are glitches.
I haven't tried the PS Vita version but there are some stuff with the PS 4 version as well. I've contacted the developer on Twitter and told him of what I've encountered so far. The most troublesome thing is that the save files on PS 4 were suddenly gone but the reappeared when I restarted. And then there is the thing with the contents of chests sometimes change when you pick something and go back to pick up the gear you just changed and then there is another item there and not the one you dropped. Without the enemies/ghosts in the completed rooms it would be basically impossible to complete this with 100% trophies as well. It's a small comfort when playing on Hell difficulty but at least it makes it a bit more bearable. Also, another problematic thing is that when loading the save file, the coins are reset to zero, and that will be a big big problem for the 8000 coins trophy unless that trophy as well as the others (8000 enemies etc. are accumulated across games).
Edit: I just got the Rich Man trophy for 8000 coins and it is accumulated across runs thankfully because it unlocked on my current run with only 3210 coins