Since they don't come w/ unity packages like the purchased models, can I change sit animations, facial expressions, menu etc?
You can if you have the files for them
@april5559 If you have the VRCA you can convert it and you will be able to work on it in unity. Keep in mind it's just like getting a package from a creator, you will have to fix a lot of things
RipperStore Official. Your Website for Game Relevant Assets.
DM me for any issues