After scoring a few early hits with 2004’s “Napoleon Dynamite” and 2006’s “Nacho Libre,” writer/director Jared Hess landed on some hard times, struggling to match the financial success and pop culture ubiquity of his initial efforts. It’s been eight years since his last feature, “Masterminds,” and he’s now making a comeback in the realm of animation, joining co-director Lynn Wang on “Thelma the Unicorn,” which is an adaptation of a popular Aaron Blabey (“The Bad Guys”) children’s book. The elastic ways of cartoon antics plays to Hess’s strengths, and he’s clearly under orders to oversee a “Sing”-like study of animal dreams in the world of musical performance. “Thelma the Unicorn” is familiar all around, but it presents its intended audience with a colorful study of identity and friendship, also delivering a soundtrack filled with lively tunes to carry the picture’s thin premise. Read the rest at Blu-ray.com