The lavish new staging of Lehár’s effervescent operetta The Merry Widow is the Met debut of Broadway director and choreographer Susan Stroman. Soprano Renée Fleming adds a new character to her Met repertory as Hanna, the rich widow. Sir Andrew Davis conducts the cast that also includes baritone Nathan Gunn as Danilo; tenor Alek Shrader; baritone Sir Thomas Allen; and Broadway star Kelli O’Hara.