Disney has 100% ownership of the kingdom hearts IP and all the characters made specifically for kingdom hearts including sore, riku and kairi, so they don't need to license anything to get it made except for the final fantasy characters, the reason why the show was never made was because it was pitched during a time when Disney still didn't have any faith in kingdom hearts, but now they are aware of how popular and profitable kingdom hearts is (sora getting into super smash bros ultimate is proof how popular kingdom hearts has become), so if seth tried pitching the show now it would almost definitely get the greenlight
