I'm trying to figure out why I feel reluctant about zombies when the idea of a dybbuk counting in a minyan gives me no pause at all. Does it really just come down to the neshome? Or would a zombie as conventionally defined be too impaired to be eligible, in the same way that I believe that being sufficiently shitfaced can disqualify a person under normal circumstances?

Basically, iIrc, the zombie is both impaired/inebriated by its core desires and cannot elect to pray and have it mean something, whereas a golem is alive and can choose (or follow an order? Slightly sketchy) and a dybbuk would have to choose to come back closely enough to join a minyan. Prayer is a free-will act and requires intent. Zombies just require high-cholesterol, easily masticated protein sources.