I won’t rule out Nora joining up with Mia, William, and Connor Hawke for a spinoff if that happens, as stranger things have happened and an Arrow future-set spinoff hasn’t been ruled out.
Still, the nature of the flash-forwards could mean that there are more or less two finales in one episode.
In seasons past, finales have served to bring the flashback action into the present, but that obviously can’t happen with the flash-forwards unless time travel is in play.