I am assuming default player in sr and sr 2 in sr4 uses one solid mesh like the rest of the npcs.
I think the outfits is not possible without SDK, as the outfits is one mesh with the body.
Playing as a npc will require hexing in the default character as a outfit... if it does not fit properly, you must somehow render player character invisible (like through texture editing?)
I think it is likely possible, but it is hard without the right tools.
Sorry for bad English.