Yep, any character. However, instigating clique wars can be done in easier ways.
Yeah, there are.
I remember changing skins as Derby, or Johnny then I'd punch one Prep, bring him to the greaser turf, then run back to the Prep hangout since the other greasers would be following then an all out war began.
I like doing that with the jocks as they put up more of a competition.