I would suggest that both pets have growl on. There will be times (especially when multiple adds come in play) that a pet will die. If the pets are already fighting for aggro it will really help in the switchover to the new pet tank. As cute as they are they are expendable and as long as they can hold aggro for a few seconds it usually gives enough time to regain control. Whether you choose to revive (<3 the fast res talent) or trap the adds.

That or get 2 piece T5