It was an up-and-down day on Friday for the filmmaking team behind the documentary “Selena y Los Dinos,” which tells the story of Tejano music legend Selena Quintanilla and her family band.

“Selena y Los Dinos ... are gut-wrenching images of Quintanilla’s family and fans grieving after her death nearly 30 years ago. But the heart of the movie is footage that has never been ...