I have thought about Happy Days made into a movie. As far as the original cast not being a part of it, wow, I don't know who could be who!I just don't see it going in that direction. I can see the original cast doing the movie very easily though.

Actress - filmography
1968: How Sweet It Is! as Little Girl
1968–1969: Daktari as Jenny Jones
1969: Death Valley Days as Mary (2 episodes)
1969: 80 Steps to Jonah as Kim
1970: The Courtship of Eddie's Father as Emily Ruth Gustafson
1970: The F. The suit claimed that cast members had not been paid for merchandising revenues owed under their contracts. In 2008 Erin Moran was a contestant on VH1's reality show Celebrity Fit Club.

Erin Marie Moran (born October 18 1960) is an American actress best known for the role of Joanie Cunningham on Happy Days and its spinoff Joanie Loves Chachi.