Aerie and Jan both make effective mages: not the best, but they're reasonably decent. The upside is that Aerie is also a fine cleric (she can actually use trigger spells to chain clerical and mage spells together), while Jan is probably the best thief in the game.
Or you could try and add Edwin into your party. If you keep your reputation from getting high enough or low enough to cause griping, everybody should in harmony. At least, that's the theory.
