the faq says:

Q: Can a ship spend an evade token to reroll a die and wait to see the result before spending another defense token?

A: Yes.

It refers to the defender waiting...

But there's nothing that allows the attacker to use the newly rolled accuracy result, as the time for assigning those accuracy results has passed? Or would that only be true if the defender spent all its defence tokens first?

I'm confused...

Gut feeling. I would go back to the modify dice rolls step for the evade reroll. Then go back through the steps. You can then spend the accuracy and other effects and the defender still gets to go through his defense token step again.

NOPE!

You only go down the list never back. So if an accuracy is rolled it is pretty much a blank die