Great news! Firefly will be back!
Though they should have set it after Serenity or featured different characters. If their fate is known, the stakes are much lower.
Yes, I know they want to include Wash.
But I think that could be done with creative writing.
Maybe the crew discovers he uploaded his brain into the ship's computer, so that he could spend more time playing dinosaurs.
Comes back as a robot, but a really cheap one that's always falling apart. Then they could have him make references to all of Tudyk's other robot roles.
Or maybe they discover he sold his DNA to pay for pilot school. So there are an unknown number of Wash clones wandering the 'Verse.