Decoration and signaling can be functions of clothes. But just because it is used for decoration or social signaling, doesn’t make it clothing. For example, jewelry isn’t clothing. To me, at any rate.
Sure. Not the major function, though, which has always been protection from the elements.
It could also be about decorum*, which is not the same thing.
- which is etymologically related to decoration.
Possibly - I’m a gradualist on behavioural modernity, largely because Southern African archaeology points that way, but AFAIK, the jury is very much still out.