What proves once more that it is an Atlus IP and thus S-E must get Atlus' permission to do anything with it.
And the same goes to Kingdom Hearts. It is not an S-E franchise. It is Disney's. It's a franchise that includes even
Mickey Mouse, the Disney's mascot. Ok, S-E done way more than just distribute it, but they need an agreement from Disney's side for S-E add some keyblade weapon, a Organization 13 robe (I would like it) or a Sora minion.
Remember, before even doing KH3,
S-E needed to convince Disney to even allow it.