Which two characters were originally omitted from the Gilligan's Island theme song and opening credits?

Gilligan's Island was created by Sherwood Schwartz and ran from 1964 - 1967. Originally, the theme song (composed by Schwartz and George Wyle) listed Gilligan, the Skipper, the millionaire and his wife (Mr & Mrs. Howell) the movie star (Ginger) "and the rest". After the first season, Bob Denver (Gilligan) advocated for Russell Johnson (Professor) and Dawn Wells (Mary Ann) to be added to the opening credits.