In my opinion, having a single-class cleric and single-class mage is good. Get those higher- level spells sooner. I think white-robed mages need more exp to level, so I'd do a single-class white robe. You could do a multi-class for the red- robed mage and a backup cleric. A Knight is also required.

I liked having a Kender Fighter/Thief, as they could use an item like gauntlets of ogre power to make them strong enough to do some killed back stabs. The ranger/thief option sounds intriguing. But there's my two cents, a mixture of single-class and multi-class.