They're not going to do a Kingdom Hearts crossover in FFXIV. If you put Capcom, Yokai, Garo, and Sega together, they'd still be a speck compared to Disney, and no company in its right mind wants Disney calling the shots on its core product.

The death of Marvel vs. Capcom Infinite is a pretty good example of Marvel making impossible demands and creating design limitations that doomed Capcom to failure, and Marvel is just one tiny part of Disney's golem.