For incorrect thought experiments. You cannot conceive p-zombie from first point of view, because there's no first point of view for p-zombie. If you conceive p-zombie from third point of view, you cannot be sure that it IS p-zombie, because you aren't God and p-zombie is identical to not-p-zombie from third point of view.
If there's no changes in behavior we usually associate with consciousness, then why we decided that those neurons were responsible for consciousness in the first place?