Yup, I think you’re right, and that I’m wrong.
Also, in regard to your edit: this doesn’t really have anything to do with relativity. Newton would’ve come to the same conclusion.
As for the two images, it’s well covered on PBS Spacetime’s overview of the Alcubierre Drive from several years back that if a bystander were to observe a FTL craft traverse their field of view laterally, they’d indeed see two images, each heading in opposite directions, as you indeed allude to.