Took this guy out today while doing Hunter achievement wasn't quite as hard as I thought it would be.
Soul Taster parsed at 965K HPs. (killed in 66 seconds) Max hit on 95 SK with about 8K AC was just under 7000.
Each of the adds seemed to have 50-60K hps, and did indeed spawn 2 at a time. Though it took 13 seconds before the first two popped up, then another 37 seconds before the second set showed from the first being killed, I didn't get to a 3rd set. I killed them all before they managed to get off any spells.