Quarterstaff seems like a good weapon.
Feats: Brew Potion, Improved Counterspell, Spell Mastery, Extend Spell?
Skills: Concentration 9, Knowledge (arcana) 9, Spellcraft 9, Knowledge (nature) 6, Spot 5?
Should we maybe give these a bonus on Climb checks or a Climb speed?
0 - read magic, detect magic, prestidigitation, touch of fatigue
1 - cause fear, ray of enfeeblement, unseen servant, protection from good?
2 - summon swarm, fog cloud, blindness/deafness, ghoul touch
3 - vampiric touch, summon monster III, hold person