You have to sell your gear to the peddler

Exactly where I said, when entering in the room, just open the wardrobe and it should be in there

You mean the one you get in the wardrobe of the succubus?

A bit of a bug I've discovered:
using the hyper-growth potion in the new fancy room brought me back to the old room on the hallway. Everything was sort of sequence-broken there (I could enter into the Incubus room and everything was in place, but could not interact with the untouched bed).

By taking the elevator down to the foyer and then trying to get back into the room, I get spat out into the fancy lounge again. (does not work with the beads potion)

So yea nothing major, but that might be worth fixing (either that or making the hallway directly accessible).

I too had some issues understanding which sinks had to be turned on and off... (unclear if the X signified open or closed faucet)