I like having more frontliners than ranged characters. I'm going to suggest some kind of paladin multiclass, because I think they
- are nice and easy to play (just use the full attacks and you're probably not going too far wrong in 80% of fights)
- make the game more forgiving (lay on hands, armor and heal aura, reviving and liberating exhortation - all good for a first time player)
- require very little micromanaging. (I don't know about your personal tolerance for micromanaging, but I have very little patience for it!)
I think something like Kind Wayfarer / Rogue or Steel Garrotte / Rogue, dual wielding weapons should deal respectable damage while providing decent support. (Could even take Trickster subclass for more survivability buffs)
I think rogue multiclasses make basically every non-spellcaster better in some way - sneak attack + deathblows in the endgame is just a truly silly amount of damage. So I wouldn't feel too bad about having three in one party.