Karlach is going barb 2 then paladin 6+ until she needs a level in the totem of the bear to keep frontlining.
My main is going to be a skill monkey, so SH and Gale will probably single class. Maybe Ranger 1 for SH so she has access to better weapons for her Dex build or maybe heavy armor and Str.
I like the idea of her and my main taking their 2nd level in ranger because they think they are going to have to survive the wilds after they crash land.