Oyster Bake, one of Fiesta San Antonio’s best-attended events, lifted the curtain Monday on a portion of its musical lineup. Veteran Tejano singer-songwriter Gary Hobbs will headline Friday, April 19, the opening evening of the two-night festival at St. Mary’s University. San Antonio-based Tejano band La Calma and Alamo City Latin-pop act Vanita Leo Music will also help round out that night’s bill.