While everyone else was based in Toronto, Frankie Muniz recorded Mo's lines from Los Angeles.
The Oh Yeah! Cartoons short "The Boy Who Cried Alien!" (also created by Guy Vasilovich) was more or less a prototypical version of Moville Mysteries; both the short and the show use the same school principal character, who is shown being beamed up by a flying saucer in the Moville Mysteries intro.
Guy Vasilovich originally imagined the show as a kids' book series, even creating a book version of what would eventually become the script for the pilot episode "Raiders of the Lost Jock-Strap". This version had several elements seen in the pilot for the TV show too, such as Moville being the name of the setting instead of the protagonist's surname.
Fox Kids was given the broadcasting rights for the show in the United States, but they never bothered airing it. As a result, the show has never actually appeared on US television, although it did air on international broadcasts of Fox Kids, including during its Jetix era.