I am currently leveling up 2 more chars to support my Warrior+Warlock+Priest team for PVE

But I am not sure what chars to take. One slot will be filled with another Warlock. That gives me one slot to fill.

The options I consider are:

+1 Warlock
+1 Mage
+1 Moonkin Druid


Warlock:

3 Warlocks would keep it easy. One would go Demonolgy and 2 Affliction.

Mage:

AI, Water, Teleports and good dmg? Sound good to me. The two Warlocks would go Destuction for better Synergy.

BUT! I got a Level 70 Mage on another Account, that supply's Teleports, Warter and AI already.

Druid:

Gift of the Wild, Moonkin Aura, Backup Heals, and a backup Tank.

Any advice for me?