IIRC, KH2FM had elements taken out that could provide more space on the disk:
Ex.
Land of Dragons Changes:
The morale gauge depletes at quicker intervals requiring the player to finish the missions faster.
Beast's Castle Changes:
Conditions to end the battle in the Living Room have changed (Either connect 100 hits, go below 30% health or battle for ninety seconds)
Cogsworth gets tired more
Olympus Coliseum Changes:
The time limit for which the player must defeat Pete, while protecting Megara, has changed from 2 minutes to ninety seconds.
Disney Castle changes:
Enemies do not drop prize boxes while protecting Minnie
Timeless River changes:
Changes have been made to the four time window battles
Agrabah changes:
Conditions to end the battle in the street have changed (Either connect 100 hits, go below 30%, or battle for ninety seconds)
The battle at the Sandswept Ruins has changed (enemies do not drop prize boxes and the time to activate the switches after examining the monument has increased from thirty to forty-five seconds)
Stuff like this that clears up some space that allows for more elements.