We did them Nightbane, Netherspite and illhoof in that order.
We killed nightbane on only our 2nd ever try but then took 6 tries to kill him the following week, a good stance dancing tank if you are horde if you are alliance easy mode with fear ward.
netherspite needs people to be awake and understand the beams, we use 2 tanks who take the green and red in alternate phases, it means you can count them out completely if your tanks are reliable, the dps just need to do their thing in the blue beam then. Have your shaman drop lots of totems at his feet before he banishes as for some reason he loves to target them with his netherbreah, this saves raid damage.
Illhoof is a pain, make sure you have full 5 stacks of wound poison on him at all times, dps the chains the second they appear and focus on illhoof the whole time, we just let the imp die from aoe damage as and when. Warlcoks casting seed of corruption on boss and calling for AOE if the smaller imps get too much. make a target demon macro so you cna find the chains easier, all dps must get on the chains as soon as they appear.