Looking at the stance of the overfiend in those pics im putting my money on it using the same skeleton/model as the doomguard. Doubt it's using the tauren model.
Still gotta love the comments about "reskins". A hundred comments about what a "reskin" means and people still dont get it. It's even the newest trend to complain about reusing models now. People need maor fresh air.
Why should Blizzard have to make new models/skeletons each time they come up with new mobs? I've never seen this much complaints about this in the last 6 years until now. Djeez.