Soprano Lise Davidsen is the aristocratic Marschallin, opposite mezzo-soprano Isabel Leonard as her lover, Octavian, and soprano Erin Morley as Sophie, the beautiful younger woman who steals his heart. Bass Günther Groissböck returns as the churlish Baron Ochs, and Markus Brück is Sophie’s wealthy father, Faninal. Maestro Simone Young takes the Met podium to oversee Robert Carsen’s fin-de-siècle staging.