So I found this item..

[adeyke]

The reanimated monsters are on your side. However, they don't really do a whole lot. They just wander around (they don't follow you), fight a monster if it's nearby (without dealing a whole lot of damage) and die by themselves if you wait too long (like a necro's reviveds). So they're free tanks for a short time and they remove corpses, but don't expect them to kill things for you.

And yes, the RIP property on Nature's Peace does stop the reanimation.