Okay, I'm having no luck so far on how to make the map marker in the warden's room disappear once I take the spare uniform. But, here's some updates on what I've done so far:
- In "Project Y", there is a bottle of chloroform and a first aid kit in four rooms - the room with the marked scientist, the smokestation room's cubicle, the teacher's desk in the classroom, and in the laboratory next to the safe. There's also a spare officer's uniform in the shower room before you take the corridor to the cyclotron.
- In "Embassy", there is a chef's uniform in the kitchen. Apparently, the chef can go upstairs without being told off, but can't enter the staff lounge. This is where a spare agent's uniform comes in. You can find it in the room with the kissing couple.
I also had a go at placing a German soldier's winter uniform in "Winter Cold", but I encountered a problem - Strogov wears TWO hats in the same uniform (the cap protrudes a little bit from the helmet).