At Rider there’s a pretty good amount of crossover. MT majors and Acting majors take a lot of the same acting classes, and everyone gets to audition for all the shows. (MTs are required to audition for both plays and musicals; Acting majors are only required to audition for the plays, but can and do audition for the musicals. At least this year, it seemed like there were a lot more MTs in plays vs Acting majors in musicals, but there’s also a lot more MTs than Acting majors so that probably plays a role in it.) Acting majors can take voice lessons, but we have to pay for them; for MTs it’s part of their major. Acting majors can also take dance classes if there’s space, but there wasn’t this year. I’d say it’s probably easier for MT majors to crossover to Acting than it is for Acting majors to crossover to MT.
Northwestern is another program with a lot of cross-pollination between MTs and straight actors.
Put Ball State on the list. Music theater and acting students each are cast in plays and musicals, showcases, etc.