Could mix and have different effects for buffs similar to AST cards but based on Rikku's mix command in FFX. Mixing different abilitkes results in lowered mp use/tp use/haste/etc. Their lv3 LB would have to be Megalixir, but obv would just heal HP and Raise. Dps skills could be the various poison/venom potions but named differently from actual items, a napalm bomb that acts like Flaming Arrow, cluster/frag bombs and cast animations could be the Chemist mixing powders and vials together. Their main weapon could be uhhh a single wield knife? Or maybe a hand gun (opposed to MCH's rifle), or a beaker but that seems kinda dumb. Maybe a Mace since maces don't really exist in this game outside of Armorer and Blacksmith weapons.