One problem with this is that they only have about three interrupts (1 tank, DPS Shaman, Hunter?). 4 if you count the Holy Paladin, but since healing was apparently not something he was capable of in the fight, I don't think I'd trust him with interrupts, either.
I'm not sure if the Warlock pet ability interrupt works on those adds, nor am I sure they'd have the fel puppy out.
Silence works on the adds (though the 45 second cooldown sucks), so I don't see why Spell Lock wouldn't work. I guess a Warlock could run with a Felhunter for Horridon.