My team after some adjustment is: Cap at lvl 49, 5R and skill upgrades; Teen Groot at lvl 43, 3R, and skill upgrades; Thor at level 36, 3R; Star-lord, level 44, 4R; and Spider-man at level 44, 4R.

I’ve used Rick Jones as well but he’s only level 30.

I’ve lost one fight so far and have 2-starred the map.

Good luck! I’ve been getting mostly 1 feather per fight, though I got one 3 feather fight. Apparently it’s possible to get no feathers. And each battle takes 7 energy things. So it’s really a grind.