“101 Dalmatians” is a powerful story about family, animal cruelty and the triumph of kindness. It grabbed audiences in its first incarnation, the 1961 animated version, and it continued to warm hearts in the 1996 live-action version of the film. What could be more heartwarming than this classic story performed by the elementary school cast from StageDoor Theatre? On Thursday, May 10, the young actors from the Conifer-based theater open their production of “101 Dalmatians Kids,” a rollicking musical version of the canine tale.