I can't really help you with your problem (I don't play alliance and have no clue about deadmines), but I want to level a similar team 4x hunter and 1x shaman.

I don't plan to do instances in lower levels. I will stick with Barrens quests and grinding mobs.

For instances I recommend at least to get 2 owls with screech for aoe tanking and for bosses a turtle with shield. I dont know the exact level for the pet spells.

I think with level 30+ instances will get easier.
skills
lev 28
Frost Trap
Arcane Shot Rank 4

level 30
Feign Death
Multi Shot Rank 2

bm talents
level 30 - Intimidation (stun and more aggro for pets)
level 31,32 - Bestial discipline (more focus for pets)