Stitch was included because a survey said that Stitch was the second favorite Disney character in Japan.
Several actors and actresses did not reprise their roles from Kingdom Hearts (2002): Billy Zane as Ansem, David Boreanaz as Leon, Mandy Moore as Aerith, Lance Bass as Sephiroth, Christy Carlson Romano as Yuffie, and Sean Astin as Hercules. Some fans highly disapproved of the use of such people playing the voices of the Final Fantasy characters, particularly Mandy Moore and Lance Bass. Interestingly, Sean Astin was replaced by the actor who originally voiced Hercules in the movie, Tate Donovan.
The producers of the game took a poll to see if Maleficent should come back for the game. The poll numbers reached ninety-five percent for "Maleficent to come back", so her return was added to the game although there is no boss fight with her.
Yen Sid is "Disney" spelled backwards. This game also marks the first time that Yen Sid speaks, as he has remained a silent character since his debut in Fantasia (1940).
When "X" is removed from Xemnas and the letters are rearranged, you get the name "Ansem". Applying this to Roxas and Xehanort gives "Sora" and "no heart", respectively. This is applied to all members of Organization XIII, as their names are their real names rearranged and an X added. However, only the original names of Ansem the Wise's six apprentices (Xemnas, Xigbar (Braig), Xaldin (Dilan), Vexen (Even), Lexaeus (Aeleus) and Zexion (Ienzo)) are given in the game.