I don't really want to comment on each individual battle, but FMA verse would probably win. Avatar chars have somewhat superior physical caliber in general, but the homuncui make up for that.
I hope you don't mean the ones from early DBZ because they would definitely lose. Though any one of them could take out most of avengers by themselves, even the three of them combined could not take out Thor and Sentry. Thor and Sentry could also solo the rest of Avengers.