Imagining rewind you assuming these mechanics, spatial causality, which is precisely what prevents free will, but it is what has to be proven.
I'm sorry, but I don't understand your phrase, neither do I understand why spatial causality would prevent free will at all. The rewind argument is just a logical conclusion from libertarian free will: all conditions being the same, you will choose diferent things if the same thing happened twice. If it didn't, that means it's deterministic.