I say keep the pally ret, unless you plan on doing lots of instances. At least until 70+, it's be easier to just kill stuff faster than bother healing. It can get tricky managing a second melee, but once you get used to it it becomes second nature. Plus adding a ret pally gives you more chances to proc Replenishment, which is always nice

And Having played shadowpriests, they are kinda nice, have some nice utility, but are tough to keep the DPS up. Holy priest makes a great healer too, so at least you have that as an option in the future.

I was leveling a RAF duo of druids, and brought along some random extra toons, and brought a BM hunter, and even with just autoshot, he does pretty decent damage, and you can get some nice pet buff/debuffs, so I think a hunter is a good choice.

Bear tanks are fun! A few self healing options helps cause you aren't always looking at the healers screen.

Moonkin. I think leader of the pack and boomkin aura cancel a bit of each other out, but not entirely. Still a good choice. You might want to swap for a lock or a mage. Summons or portals might be of more use to you.