So, my initial run was as a Tiefling Entertainer Wizard, and honestly I had a lot of fun with that. In the final game they'd likely be an Illusionist or Enchanter. Wizards get a lot of spells and it makes every scroll you find a boost, however mild, to your overall versatility (especially if they don't alter Wizards getting to nab non-class spells), so it could be a fun first playthrough.
I admit, though, that's not amazingly inventive or up for multiclass shenannigans. I'll also weigh up whether I want Wizard or Bard: keying off Charisma and getting a small boost to any skill check you'd otherwise flunk, well, that's tempting for the poor "never fail a check" urge inside me.
It's tough to say how I'll develop the companions. I'd feel a little silly giving Astarion, say, Barbarian or Druid levels. Lae'zel I'll probably make a Battle Master and Astarion a Thief though -- they're just the subclasses of Fighter and Rogue I find most fun to play right now.
If they develop the nonlethal side of things a bit more, I might try for a pacifist run at some point (right now KOing the goblin leaders just makes the plot and everyone in it react as if they're dead). My gut plan: Paladin 2 / Lore Bard X. This basically squares Bard's weaknesses (squishy, usually not primed for melee attacks) by giving them armour and Divine Smite.