I hit area 57 and progress is impossible. Alivebeard spawns before the objective clears and instantly wipes the entire formation and fails the whole objective on the spot. Maybe I could use drop rate increase crusaders, but the kids swapping around every 50 areas makes the strat unreliable. Plus, I'd need to idle every 50 areas to figure out how to set up the formation for the next 49 areas to maximize drop rate while also not getting nuked by Alivebeard in that area while changing things around.

Unless I've missed something, this doesn't seem possible.