A dream cast assembles for Strauss’s grand Viennese comedy. Soprano Lise Davidsen is the aging 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 baritone Markus Brück is Sophie’s wealthy father, Faninal. Maestro Simone Young takes the Met podium to oversee Robert Carsen’s fin-de-siècle staging.