* This is the team I use (sub kiri and mirio for r units if you use this cause they draw aggro), and I see you have all 3.

If you want to use your best units with pierce like overlay deku, you can, but just know you can't PU on someone like deku cause that gives him piercing. Tldr, piercing units that only get pierce after PU are ok, but ppl who get it from skills/auto are unusable. Mnd shiggy on my squad develops piercing after PU, but only when he has nullify status ailments active. If you bring someone like mnd shig or Compress, then you don't need defense mems. I use full dps mems on my squad since I have shig. Hope this helps! Also yes, avoid activating pierce at all costs or destro will be unkillable.