This article clearly shows Lauren Tewes was on board to come back as she did for the Love Boat specials and even for the 10th season if it had happened. Why was she not in the final episode Happily Ever After at the Captain's Wedding? THis aired 5/24/1986 so it would have been filmed I would think after the newspaper article. Also she had guest appeared in the Trouble in Paradise episode aired 11/30/1985 so it seemed all would get along and together for this.

http://news.google.com/newspapers?nid=1345&dat=19860103&id=37ESAAAAIBAJ&sjid=t_kDAAAAIBAJ&pg=2149,451167