Laezel and Astarion could reclass to any martial class really.
Laezel wants to be a githyanki knight which would be a high end eldrich knight, however her story seems to be trending words breaking with gith culture so it might not make sense late on.
Astarion again can fit anything. If you give him the necromancy of thay, going arcane trigger or even just full on reclassing him to wizard might be good.
Let's make Shadowheart a Paladin.
