In the Dread Realm the Reanimated are stated with 2 Threat, 2 Attack, 2 Defense, and 2 Hit Points, but I didn't see anything about engagements levels.
Usually they're going into play directly engaged with you, but the Possession treachery specifically says that it goes into the staging area. Plus there are a few player cards that can send enemies back into the staging area as well.
How do you interact with them in the staging area and the engagement phase?
I was playing that they just stayed there, but could be optionally engaged, but I have no idea if that's right.