There's going to be free love and everything, so I really don't see what the problem is. This is about as AU as you get, so there needs to be a really cool and fun Peter to be the fourth Marauder, and get into trouble and go on kitchen raids and did I mention SLEEP WITH AFOREMENTIONED HOT GIRL WINK WINK NUDGE NUDGE so get on it!
hem. /vehement pimpage.