Kingdom Hearts I consider to be more of a straight port. It's just the Final Mix version with better performance and higher resolution. There's not really any possible reason to choose any other version than the PS4 one, so it shouldn't count.
-Re: Chain of Memories had changes to some of the card rewards and I believe added reaction commands, though that may have been in the original PS2 version.
-Kingdom Hearts Final Mix added reaction commands, which was pretty big
-Birth by Sleep Final Mix and Dream Drop Distance are ports from portable to console.
-Not sure if the Kingdom Hearts 2 Final Mix port added anything or changed anything up.
Honestly though porting the Final Mix games from Japanese is pretty cool though. Very much a brand new game for a lot of people who weren't going to go the very extra mile to play those.