Nearly a decade ago, Jake Heggie and the librettist Gene Scheer created an instant American classic with the epic Moby-Dick. The latest of their many projects, If I Were You, tells of a latter-day Faust whose soul invades other people’s bodies, at catastrophic cost to himself and to them. “Will you live forever pretending to be someone else, or will you die for love as yourself?,” Heggie says. “That is the question.” Watch the two alternating world-premiere casts for stars of the future. Like a handful of other durable operas (Purcell’s Dido and Aeneas, Tchaikovsky’s Eugene Onegin, Mark Adamo’s Little Women­­), this one was written for conservatory students. —M.G.