So, kinda like in CK3 barbershop when you can take all clothes?

It's in my opinion somewhat duable but rather tiresome. I will not explain it fully, and suggest you to refer to CK2 modding wiki pages.

The idea is - CK2 have some artifacts that alter character clothes like helmets, when you wear them. So, if you want ability to put certain clothes you can find those artifact figure out how it's work, then create custom artifact that tied to outfit you want and make player-only desicion to give your character one. Then when you equip it - your character will have that cloth.

Alternatively you can make trait, when also work in same way and give char who have that trait that clothes. as traits can be invinsible you just need to make one trait without icon, and then character-decision for player only to apply/remove that trait when you want to put that clothes on or off.

That's the theory. I will not explain it further, as i make anything mod related for CK2 more than year ago, and currently feel tired. But i hope it's give you some insight on how you can done what you want to do.

P.s. On trait that make character wear certain outfit you can check warhammer mod, as chaos-choosen traits alter character outfits in it, so you can use that as reference of how that work.

Modding questions are best asked at

https://forum.paradoxplaza.com/forum/threads/modding-quick-questions.589686/
or in the
"CK Modding Den" * 'server' on Discord
or the
"ck2-mods" channel, the latter being part of the official"Crusader Kings" 'server' there.


Though graphic modding folks are not around that much.


*(or whatever its called, haven't been on there for a while)