No, the whole point is if you have two entities, one of whom is a zombie and one of whom is conscious, there must be some physical difference in their brains. ('p-zombie' normally is used in the context of the (impossible) thought experiment where there is no physical difference in the two brains, but only one is conscious.)

Please don't misunderstand -- I agree with all of that! I meant that the whole point of using the term "p-zombie" is to specify a being with the (hypothetical) properties that it looks just like a human (or being that is normally accepted as conscious), in all physically discernable ways, but (somehow) lacks consciousness. So I was confused as to how it could affect the storyline for some being to be specified as a p-zombie, since you wouldn't know the difference.

I agree that such a being can't exist, for the standard reasons.

If the vampires actually have different brain architectures, then they shouldn't be called p-zombies, because they don't have the form of something normally conscious, like a human. It would make as much sense as saying that a rock is a p-zombie.