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.

You're right that the term is being used incorrectly (or at least very loosely). However, I think it makes slightly more sense than calling a rock a p-zombie, since the vampires in Blindsight do behave like humans and have normal conversations like humans: that is, they would pass the Turing test. Entities like this are sometimes called "behavioral zombies" (as opposed to "physical zombies"), and it's not clear whether they are possible, though Eliezer seems to think so.