Questing will be much slower than boosting them in instances.

As soon as my teams hit 10 it's off to Deadmines and then instances all the way to 80.

You're going to want to get a few more levels on the Shaman if your going to boost with him/her. HoL at 82 will be slow if doable at all. My advice is get to 85 with the shaman, go to Pearlfin Viallge in Jade Forest (MoP) and they'll be a vendor that sells 372 ilvl gear (it's cheap probably 500-700 gold for a full set). HoL won't be a problem with that gear.