Because your extras are casters, you can just have them parked/stopped in each section that you plan to pull. Personally, I like the warlock as opposed to mage. I like the efficient and slow DPS of DoTs as opposed to the risk of taking aggro with a few crits. The addition of free dps as a pet, or imp for HP buffing, would help too. Either should work though as a good 'Sheep' will beat 'Fear' in an instance just about every/any time. I have been toying around with the possibility of 3-boxing UDs DK+Lock+Priest as well. With the lack of shield and 2nd healer, it may not be as efficient, but I will give that up for having 3 UDs for the sheer looks and 'evil' factor anyday!