They do not have closets in the walls. Your wardrobe may have a mysterious land full of talking animals and magical creatures hidden in it, but mine didn't.
All rooms have their own sink and mirror.
In County College, you will have a window seat instead of a second chair. I have experience with rooms in Bowland, Cartmel, County, and Grizedale colleges. Rooms in the other five colleges may differ. Bring sheets, anyway. The university will provide you with sheets, but there's no knowing who's had them or what's been done with them.