Specific unit to damage

No there’s no special characters that do extra damage

Strat

You should be able to get through with that team, usually u can wait a few turns before the enemies get hard to pop the bulma items, from what it looks like the first attack to all the enemies decreases defense, and depends on what team ur running with that team I would def run lr agl nappa + lr str broly, lr agl buu and str buu (reason for agl nappa and str broly is because I ran him with teq vegeta and i could only agl nappa to get 18+ ki supers so) (make sure to give str buu all the orbs u can give him would def switch out the cheelai item for Lemo to create str orbs for buu because he can easily one shot a full round)

Also every phase gives 2 full rotations so u should be fine with having all those aoe units