Last November, Neil Firstenleit, a local “kindie” music celebrity known as Mr. Singer, opened a school for tots that has become the one parents clamor for. Operating out of a storefront beneath his Lake View home, Firstenleit runs group music classes in which kids from six months to six years old sing, dance, and, best of all, play with his collection of instruments from around the world—guitars, kalimbas, mandolins, ukuleles, and synthesizers, to name a few—all displayed on a massive wall.