Yes, the north wall is intended to be lock boxes for storage of assorted staff essentials. The decorative chests you earmarked would suffice for that. You certainly can shove the stool off to the side and add a small door into the bathrooms from the locker. Basically, the 'robe closet' is for people who come from outside to ensure they are appropriately dressed and clean to approach the Emperor and/or Empress, and the locker is the same for staff, though for them it also half serves as a conference/meeting/break room too. This room would be an appropriate place to put the battle table too. This room is less concerned about 'looking good'. The chairs might not match or they're just the wicker stools or the stone equivalent of a plank. I imagine that the desk and table may sometimes have all the chairs pulled up for a meeting or a game so they're left there, but other times there might be half a dozen guards doing jumping jacks and they're pushed against the walls. This room is haphazard and never used to impress anyone, just provide a place for staff to change out of dirty or smelly clothing or have a quick conversation. There wouldn't be any weaponry or significant clutter. So, the floor is probably a fairly scuffed stone. Also, there's probably a window with a curtain lined up to the window on the outside of the hall, as this would be considered a non-private space that all staff should be able to peer into and see what's going on.
There are two other rooms. 'Guard Office' has a large desk space used for multiple high ranking employees and bookshelves for case files, reports, etc. It is often and officially used and is in clean order and condition.
"Living Room" may be the most colorful place in the lot, as it's used for entertaining any meetings with people who may be important but from all over the place. In theory. I suspect the staff use it more often than it is actually used for the intended purpose, given as by now the city's intended purpose has fallen apart and it's basically a city-state dictatorship. The items in here are likely nice, as they were once intended to impress governors and councillors, judges and secretaries... In some small way it's a time capsule of the intentions before this yellow reign overtook. Also an appropriate place to stick the game table.
It all looks good to me.