I wouldn’t mind Jefferson and Emma. Though the whole he kidnapped her and her mother is an issue with regards to them finding happiness together. And the whole he was waving a gun in her face and drugged her and tied her up. He isn’t very stable right now either. Though that may work out better once he knows Emma is going to help him and Emma believes him. It is just that right now her reaction to him will probably be alarm and pulling her gun on him, but maybe they could get to romance at some point.
It would be crazy if he was related to the queen or because of his history with the queen for him and Emma to be together. I could see some back story going on there where we learn about the character and then sort of wonder about him in the real world. He would have to be on the show more regularly though and not die by the end of the season.