I have heard, from a little bird, that Joss Whedon was working towards that firefly called Serenity when he was tapped to cover for Snyder. LET US HOPE!!
^^ Coming in to help wrap up Justice League while Snyder takes needed time off to deal with the tragic suicide of his daughter. I don't know if I'd lend any credence to new Firefly rumors any more... Seems like Joss has a ton on his plate already, so maybe it's another graphic novel or something... It's a sad personal statement for me to admit I'm firmly in the "believe it when I see it" camp. ETA: You beat me to it, Starbreaker.