Golem: I would personally only do double rock golems and go for Rhyhorn for ground attacks. If you TM him to rock moves that would be a good one, but would be better with 15 attack.
Tyranitar: Just an awesome legendary attacker in general. Good choice, but again 15 attack would be better.
Piloswine: Safe investment given Mamoswine, but probably not very urgent.
Machamp: If you are still doing lots of level 4 raids this would be good, otherwise you look set for Machamps.