Plot hole: The ability of the Faceless Rebels to impersonate other people completely defies logic. For one, when impersonating someone, the Faceless Rebel is able to speak despite the fact that they mutilate their own mouths shut. Secondly, as can be seen in many instances when a person is being attacked by a Faceless Rebel, the face of the person they are impersonating is merely a skin mask that can easily be pulled off. If the face of the person they are impersonating is just a mask, then any time a Faceless Rebel speaks you should be able to see their true face through the open mouth of the skin mask. Additionally, the face of the person being impersonated being a mask would also preclude the Faceless Rebel from blinking or moving the mask's eyes (similarly they mutilate their own eyes shut, so the eyes of the skin mask can't be their own).