Maybe someone who participates in the Twitter sessions with RC could ask him if he has a lot of screen time in the finale. That might give us a clue as to whether a Rumbelle reunion will happen in the season finale.
My guesses for the finale: most of the episode will focus on MM’s trial. She will be found innocent, possibly by some discovery Emma makes, as well as Gold’s silver tongue. But, while David will want to renew his relationship with MM, she will break up with him. However, in FTL, SW and her army will be victorious, perhaps with help from Red and Rumple.