Started a new group, currently running.

Pally Tank
Arcane Mage
Destro Lock (demo at 50 for Felguard)
Smite Priest (lol till 40 then Shadow)
Resto Druid.

My team is currently 33 and blowing through SM with ease. I'm concerned though that I should swap the Resto Druid to Balance, then make my priest for heals.

Does Boomkin Form Buff stack with Demonology's Demonic Pact? I'm just wondering if Shadow Priest is going to be more/less helpful to my other casters than a Balance Druid. Thanks for the input!