I've tried finding a Yang claw combination that will bug the absorb, but none of them work. Best damage I can deal to her is via Cecil's Silver sword for 200-300. The other sisters are much easier to kill, but if it's a delicate matter of damaging the other sisters enough to finish them in 4 turns, it's really hard to tell. Takes hours of trial and error and damage logging to figure out their max HP.
I've likely missed plenty of drops in the Tower itself. The enemies I have killed haven't dropped anything, and there's several I can't kill at all (Icebeasts, Epeegirls).
One question I'd have is, does Displ change speed back to 16?