The audience at Sunday’s Broadway opening of “A Streetcar Named Desire” ran the cultural gamut, from Edward Albee to Melissa Harris-Perry, from Jessye Norman to Beau Bridges. But it was the curtain call that had people talking.After taking his bow, Broadway debutant Blair Underwood, the evening’s Stanley (the Kowalski surname is never uttered), introduced lead producer Stephen C. Byrd, who asked the first-nighters at the Broadhurst Theater “to sit down for moment, except for the investors,” whom he instructed to remain standing. At the Copacabana after-party, Byrd explained, “We have to encourage people to pass the plate!” The Tennessee Williams revival was unique for reasons other than Byrd’s moment or the multi-racial casting. Nicole Ari Parker essays one of the funniest Blanches ever. “Blanche is a survivor,” said the actress. “Wit is what gets us through.” And Underwood essays one of the meanest Stanleys ever. Which is just the way Emily Mann wants it. “Blair’s baby face gives him the permission to go there,” said the helmer.