When I was in the WT policy was to make the person live as the sex they were born. So theoretically, this couple could be accepted and baptized as long as "he" went back to living as a "she". Now that would be impossible if she was surgically changed to become a man.
Watchtower would never recognize a marriage of the same sex. In order to be baptized, they would have to divorce and the transgender would probably be told he has to be celibate until the New system where Big J will restore him back to his original sex.
Lots of people are told they must WAIT for the New System to be happy.