Jefferson Mays discusses playing the eight characters in “A Gentleman's Guide to Love and Murder.” Monty Navarro has just received some great news from his late mother’s lifelong friend—he’s a long-lost member of a noble family and could become the next Earl of Highhurst. There are only eight minor issues, namely the other relatives who precede him in line for the title. Mays plays each of the eight heirs standing in the way of Monty’s fortune—a breathtaking, whiplash-inducing performance.  “A Gentleman's Guide to Love and Murder” is playing at the Walter Kerr Theatre.