Special spiral AOE Combo

Yes.

Yes, preferably those who can end a battle with only 2 cooldown left after firing their AoE. You can't rely in doubling in case you can't or if you one-shot, so those with brave or slaying weapons (such as Cherche, Ishtar) or running Heavy Blade (thinking Lilina) are optimal. Remember a guard-effect skill will still ruin it.

Anyone without a cooldown penalty. It doesn't work with blade tomes unless you don't OHKO after the special connects.