The pally will be the hardest healer to go with, for a boxer.
They are the least mobile with the lowest AoE healing power.
Not saying it cannot be done, just that anything else is easier.

A Pally is the easiest tank to box with.
A Druid is a pretty decent tank as well.
A different style of play, but they both work quite well.

3x Elemental, can heal through all 5-man content, and quite well.
I'd consider having the Druid go Boomkin, since you're already at 80th with a good set of Resto gear.
You'd have to manage Eclispe.
If you're using a Click macro, have two... IS -- MF -- Wrath and IS -- MF -- Starfire.
Mash one until it procs Eclipse, then mash the other.
I've approximated mine, for ease of play:
Sequence 1: Wrath,Null
Sequence 2: IS,,,,,, comma's for my spam speed.
Sequence 3: MF,,,,, comma's for my spam speed.
Sequence 4: /castsequence Wr, Wr, Wr, Sf, Sf, Sf
If you have poor latency, you could turn #4 into several click macros instead.
Then pull macro's 2 and 3, for trash and put them back in for bosses.
Optionally have another for Faerie Fire, if you're talented in that, but you'll likely be hit capped for heroics without it.