Florentine Opera christened the newly renovated Uihlein Hall Friday evening by scattering litter across the stage. But wait a minute — I don't want you to think the Florentines don't clean up after themselves, or that they won't be invited back to the Marcus Performing Arts Center's flagship space (with spiffy new center aisles, but more on that later). In a COVID-19 pandemic year of local arts groups navigating safety protocols to perform unusual works in unusual ways, the Florentine's "Little Mahagonny" might be the unusualest. Composed by Kurt Weill with words by Bertolt Brecht and Elisabeth Hauptmann, "Little Mahagonny" (1927) is a six-song cantata about people who light out for a city of gold, only to discover they're miserable there, too. Weill and Brecht later expanded it into the opera "The Rise and Fall of the City of Mahagonny." Both versions include "The Alabama Song," covered by a zillion people, including The Doors, David Bowie and Bette Midler.