At the end of the Final Mix+ trailer the rocks that the Bald Mage are standing on seem to resemble the castle in Radiant Garden and Castle Oblivion. When Terra looks up to face the Mage he and the Heartless type "THING" are standing on some kind of fortress. I believe that the three castles are connected if it is indeed a castle. Radiant Garden= Light Castle Oblivion = Dawn Castle in trailer= Darkness but that still leaves Twilight= which may be Malificents Castle in Radiant Garden since she has some kind of revelation and helps Sora a few times in KH2. This is my opinion let me know yours.