Original Mary Ann
Originally, the CBC sitcom creators had a lot of casting options for the role of Mary Ann. More interestingly, Dawn Wells was not their first choice but rather a backup. The 1960s international sensation, Raquel Welch, is the original actress sought to do Mary Ann. We all know what happened next, though. Welch turned down the offer, and Wells became one of the main casts in the successful and award-winning show.
Original Mary Ann
Reference
Thurston Howell III, portrayed by Jim Backus, was a nod to another character on the show. Producer Sherwood Schwartz had another show at the time, The Alan Young Show. On that show, Backus portrayed Hubert Updyke III. When Schwartz first pitched Gilligan’s Island he said, “the island would be a social microcosm and a metaphorical shaming of world politics in the sense that when necessary for survival, yes we can all get along”.
Reference