You could make the druid a boomkin and put him in the group with the mages for the +Crit aura. Put the warlock in the tank group for the damage shield and imp buff. Do your mages blizzard for AE? You can self-cast blizzard, add warlocks to that and spec them with intensity so their Pyroclasm does stuns. (I did this with my warlocks hellfiring when leveling.)

Also, a fun trick for you guys with warlocks. The imps from Edge of Madness that you charm can tank Hakkar and do ridiculous damage on him. They also hold aggro and can't be mind controlled. Keep them healed and can make the fight easier. My guild does it sometimes, depending which of us warlocks are part of the raid.