I don't think I could tell a new story in that exact universe, because I don't even UNDERSTAND that universe... but something in the same vein, where a group of young protags find themselves as chosen heroes in a war to save all realities against a cosmic foe? Yeah, maybe.
But the basic premise... stories follow patterns. They have peaks of victory, valleys of defeat, meaningful connections, and so on. Some are simple and light, some are heavy. Some are funny, others thrilling, others terrifying. Some are short, some take years.
So what if a villain group could invade Disney worlds, and take away the endings for characters? What if Pride Rock never bounced back from the acts of Scar and the Hyenas? What if Riley's Emotions never got back into the control room? What if Mister Banks never learned his lesson about family?
So the team would be sent to various Disney Worlds to help ensure the stories within came to their rightful end... while exploring their own stories as well.
Meanwhile, those who have lost their own stories, whose fates or destinies had been erased, would become husks of their former selves called Neverafters...
So... I think I finally figured out the plot angle for a D&D campaign inspired by Kingdom Hearts.