I wish festival outfits would unlock in game automatically after about a month since the festival ended. I was busy during that music festival so I didn't unlock the outfits, now there's 3 T-shirts permanently locked in my game. I don't even like the shirts, but it's just annoying to see the locked shirt icon in a game I FULLY PAID for.
For context, the unlocked items are those exclusive to uniforms a single would put in when going to work. They’re only hidden so your scientist or rockstar don’t suddenly bump into a random person dressed the same way.
All the items are unlocked by achievements (career promotions, etc). Adding the gallery sim to your household unlocks them because items are unlocked per household, and the game transfers over the unlocks if that makes sense. You can also just use a cheat while in live mode to unlock all items, then go into CAS after to access them.
I was surprised when I got a random sim from the gallery before and seen my clothes stuff yellow in CAS and seen there was new stuff, and everytime I play I use that to get that tight black shirt for some of my sims