No man is a hero to his valet—which may be why one of the most revealing relationships in this Mozartean Rake’s Progress is the one between Don Giovanni, the master, and Leporello, his flunky. For a while, the two even switch parts. Yet who always gets stuck on a dark street corner as lookout in the wind and rain? Who never gets a square meal or a roll in the hay? Guess. (Contrariwise, who doesn’t get hauled away in mid banquet for an eternity in the flames of Hell?) In Washington, two well-credentialed, serious-minded American bass-baritones team up for what could be an unusually illuminating double portrait: Ryan McKinny as the boss, Kyle Ketelsen as his wingman. —M.G.