Re: townies refusing to wear their outfits
I know this sim behaviour may be annoying for you, but the things you described don't sound like bugs.
There's a special outfit category known as "situation outfit" that you can't see in CAS or control, that the game will generate for sims to wear in particular situations, for example at City Living festivals, for celebrity sims to make them look edgy, during seasons holidays, when it's raining, students at school organisation events, if they're spellcasters visiting the magic realm, and a whole bunch more.
For roommates in Discover University through, some roommates will generate with the roommate quirk of being a fashionista, and will generate completely random outfits from time to time as part of their quirk.
So everything you described is by design.