I'm still not sure if multi attacks or mass attacks would work like that? Things like Flurry of Blows and Fracture deal multiple instances of damage in one attack.
A mass or multi hit attack deals damage once with every instance of the attack (ie Leia attacks 3 times, three instances of one damage, Gk assist with 1 instance of damage from each buffed ally), so theoretically if B1 "dies" to the first attack instance, then going off other times when enemies die before the second or third instance, the character wouldn't attack again, and B1 would only lose 8 stacks of Droid Battalion?