I did it 2 weeks ago, it is not very hard:
enrage should not be an issue (at all), healers shouldn't be needed, as long people are aware of their own hp
the quests requires you to bite 3 people WHILE having Shadow's Edge equiped, you can equip another weapon inbtween bites (failed once because I forgot to change back to Shadow's Edge)
furthermore, you have to be hit be blood mirror, to do that, run in as the second person (1 runs in to tank, then you everyone else slacks untill first bite)
we had some issues with the bite, she should bite the person highest on threath who isn't the tank, but she kept biting the tank, so might take a try or two. what we did on the succesful try, the 'tank' ran in took aggro, I ran in (with Shadow's Edge equiped) got the debuff, equiped my real wep, and did as much dmg as possible (so I got aggro) and got bitten
we were 4 people when I did it (you can do it with 3 but harder and depends alot on the set-up), we had a pala (tank, badly geared), an ele shaman (useful for ankh), a SP and myself
after I got bitten, everyone started dpsing, when 1. bite came around, I bit the Shaman, he did as much damage as he could, when the debuff were about to run out he died (not easy to die mind you, as you heal yourself by dameging)
he ankhed, I bit him again, he died again, and I bit the priest (iirc), by that time I had failed 1 bite (didn't equip Shadow's edge), so we waited till next bit, priest bit the shaman and I bit the pala, and we bursted the last part.
it wasn't very hard, with a few more people it would be alot easier (but remember not to kill her), if possible, bring a lock, their life tap is very useful when they have to die + they have SS
it is very easy, you just need good communication, that is all
GL