(SPOILER) I love the theme of letting go of the past, and embracing the future! Loved how they played on the modern world and its problems. To all the people whining about the LGBTQ properties in the movie, well, last I checked it is a huge part of modern life. THIS IS MOST DEFINITELY A KIDS SHOW. They will understand, especially if you educate them properly.
Also, just because it shows a character who transitioned to a woman, doesn't mean it is "leftist" propaganda. Teaching acceptance isn't a right or left thing. It is a human thing.