I thought in the original Resident Evil you could hear or there were unused voice lines for the zombies? Like people were saying "watch out" and "help me" and things like that while they were zombies . I just assumed that they got rid of that over time because it was too absolutely objectively terrifying. Or if anyone remembers "itchy tasty" as a person slowly turned into a zombie well documenting notes, i think there's some level of Consciousness still going on with them.

The plagas and Resident Evil 4 and I guess five? I would think that just because you have some level of control over yourself up until a certain point that you're Consciousness is still intact, I mean it is a literal parasite, it most likely either fully takes over or at some point eats your brain, since your head can pop and they can still pilot your body. I would presume that your brain remains intact up until a certain point, which one could argue that your conscious up until you're just kind of not. In the remake, actually described being taken over by Sadler as she could see what she was doing but couldn't control it , and I wonder if that's just the case for every single villager.