This is a list of Canon Characters saying whether or not they are Available.
Destiny Islands:
Sora- Available
Riku- Available
Kairi- Available
Selphie- Available
Tidus- Available
Waka- Available
Agrabah:
Aladin- Available
Genie- Available
Jasmine- Available
Abu- Available
Jafar- Available
Domino City:
Seto Kaiba- Available
Yugi Moto- Available
Joey Wheeler- Available
Mokuba Kaiba- Available
Ryou Bakura- Available
Marik Ishtar- Available
Ishisu Ishtar- Available
Noah Kaiba- Available
Monster Realm:
Yubel- Available
Feudal Japan:
Kagome- Available
Inuyasha- Taken
Koga- Available
Shippo- Available
Kikyo- Available
Sesshomaru- Available
Rin- Available
Miroku- Available
Sango- Available
Naraku- Available
Elemental Nations:
Naruto- Available
Sasuke- Available
Kakashi- Available
Tsunadae- Available
Sakura- Available
Hinata- Available
Skyrim:
Ulfric Stormcloak- Available
General Tullius- Available
Arngeir- Available
Paarthurnax- Available
Vex- Available
Lord Harkon- Available
Farkas- Available
Aela The Huntress- Available
Delphine- Available
Serana- Available
Shugo Chara:
Amu Hinamori Available
Tadase Hotori Available
Yaya Yuuki Available
Nagihiko Fujisaki Available
Rima Mashiro Taken
Kukai Souma Available
Kairi Sanjou Available
Yuu Nikaidou Available
Yukari Sanjou Available
Utau Hoshina Available
Ikuto Tsukiyomi Available
Rikka Hiiragi Available
Hikaru Ichinomiya Available
New York:
Dante- Taken
Vergil- Available
Trish- Available
Lady- Available
Lucia- Available
Arkham- Available
More will be available as worlds open.