I don't really see how this is a challenge. Single class characters are pretty good.
Btw if you can't decide which companion to put in your group I recommend playing Lae'zel or Astarion as origin and failing the skill check to pull Gale out of the portal. When I played as Astarion (Thief) my camp ended up pretty empty with just Lae'zel (Eldritch Knight), Shadowheart (Trickery Cleric) and Minthara (Vengeance Paladin) as possible companions.
