zHonestly, either hunter will work with either shaman. A BM hunter will likely have a slightly stronger tanking capability, so to optimize I'd do BM hunter and shammy. I dont have a high level shammy but if it's like a druid, you have access to some healing spells in every spec, more in resto of course. I'd favor elemental shaman since you can both then dps for range and, as long as you keep aggro on the pet tank, you won't take much damage yourselves. If you use the Enhance shammy you'll need to watch cleaves, whirlwinds, etc.
Things to remember... Always misdirect to the pet to help with threat. Keeping the pet alive > your DPS so keep Mend Pet running on it and the shaman should heal it if it's getting low. You can also drop aggro as the hunter with Feign, which will help. Skada and Recount have views that show threat so you can see when you're creeping up on the pet.