PVE Team Questions regarding a Druid healer

Ok, I figured I'd post this in the beginners forums because I am actually pretty new at the "PVE" multiboxing aspect, & some of these questions might be noobish:

1. I have 2 PVP focused 5boxing teams at or 1 level away from 70, 4x mages, & a priest, & 5x shaman.

I have decided to level a Paladin, to be able to Mix & match for Heroics with the above 2 groups once he gets to 70. while leveling him.
I plan to multibox & I would really like to level him with some classes I haven't played before:

Druid, Lock & Hunter come to mind.

The question is:
1. Should I level the druid Resto, & bring an extra lock or hunter? (The intent would be to make the Druid a Boomkin at 70)
or
2. Boomkin Druid, & bring a holy priest to heal (I would spec the priest shadow at 70?)

As stated above I already have: Priest, Mage, SHaman to swap with once they get to 70 & will probably run with Tank, Priest, 3 mages once this is done.

Shadow priest and a resto druid all the way.

Boomkin has nowhere near the same utility in a 5 man group that the shadow priest has, Especially with a paladin tanking. You might want to go boomkin with the druid anyway for leveling, since most of the time reju + VE will be enough healing for the paladin to stay near full health, and at times add a regrowth at most. In addition Priest healing is nowhere near as efficient as druid healing is. However, I am certain you are going to get a lot of completely opposite answers too.

I use a druid (boomkin) / pally / lock team and enjoy it. I have the option to use a priest as well since I have one in the 60s but don't unless I really need the healing. I think the druid adds more utility w the various dots / debuffs / and burst dmg spells plus the moonkin buff for the warlock too. Also, in tight spots I like having innervate and treants and when I'm AEing the druid is useful too (of course hurricane or whatever is limited to outdoor use only). If for some reason my paladin goes down I also have the choice of going bearform and finishing off the mob or rezzing my pally back up again. I've found the druid isn't as useful when I need him for strictly healing like in a tough instance and thats when I'll choose to bring the priest instead. Anyway, hope that helps