This is a little late, but I run a team very similar and I just started clearing heroics with them. Pally tank, priest healer, shadow priest, frost mage and boomkin. These characters are filling some roles in my 10 box team and I'm gearing them together.

For the specs:
For the priest I went with the raid utility aoe holy spec on wowwiki.com. You give up some single point heals but the group heals are amazing.

The frost mage is a raid mana battery, also on wowwikiw, which is a dps hit but i like the mana even in heroics, especially with bad gear. Arcane would be better dps but I use the mage more for ports, food, and replenishment.

The others are standard specs for tank and dps.

Never tried a druid tank. I like my aoe-pally-one-button-madness. And aoe priest healers rock.