“The Simpsons” casting director Scott Muller will oversee voice casting for “The Most Serious Fart,” Utopai’s animated feature based on Mike Bender’s bestselling children’s book, which wafts into theaters in 2027. “The Most Serious Fart” follows Siegfried, an uptight fart who is ashamed of who he is and determined to change farts into something respectable. […]