Seth MacFarlane knows his stuff. He is not just an actor-writer-director; he’s also an Oscar-nominated, Emmy-winning songwriter and a Grammy-nominated big-band singer. So for his new science-fiction comedy-drama “The Orville,” debuting Sept. 10 on Fox, he demanded a 75-piece orchestra and lined up a trio of veteran composers who, among them, have amassed 14 Emmys...