In Birth by Sleep, what is the order of character arrivals at each world? By that I mean, at each world, who arrives first, who arrives second, and who arrives third?
I've listed the worlds in the order they get visited (according to the Trinity Archives timeline) then listed the order of visitors next to it. There is some overlap but I couldn't think of a simple way to show that. I've also listed names more than once on some worlds since they are visited multiple times in the course of the story.
Land of Departure - All, Ventus, Terra
Enchanted Dominion - Terra, Ventus, Aqua
Dwarf Woodlands - Terra, Ventus, Aqua
Castle of Dreams - Ventus, Terra, Aqua
The Mysterious Tower - Terra, Ventus, Aqua
The Badlands - Terra, Ventus, Terra
Radiant Garden - Ventus, Terra, Aqua
Disney Town - Ventus, Terra, Aqua
Olympus Coliseum - Ventus, Terra, Aqua
Deep Space - Terra, Aqua, Ventus
Never Land - Ventus, Terra, Aqua
Destiny Islands - Terra, Aqua, Ventus
The Keyblade Graveyard - All
As you progress through the game, a timeline is created in the Trinity Archives (accessible from the main menu). This timeline shows the order of arrival of each character at each world, and the estimated duration spent at each world. You can view the timeline on the KH Wiki, or, alternatively, I've created an interactive version of this timeline.
As a note, it wouldn't actually be possible to play the game entirely linearly, since during a few worlds, multiple characters are on the world at the same time. However, it would be possible to play the game through semi-linearly by playing through each character who arrived first at each given world.
Also note that this order is always displayed the same in the Trinity Archive, but the worlds can be visited by the player in a different order because of multiple worlds being available at the same time.
I think that the most fluid (chronologically speaking) order to play the game is: LandofD-Terra LandofD-Ventus LandofD-Aqua EnchantedD-Terra DwarfW-Terra DwarfW-Ventus CastleofD-Ventus CastleofD-Terra CastleofD-Aqua EnchantedD-Ventus EnchantedD-Aqua Badlands-Ventus MysteriousT-Terra Badlands-Terra DwarfW-Aqua RadiantG-Terra RadiantG-Ventus RadiantG-Aqua Olymp-Ventus DisneyT-Ventus DeepS-Terra Olymp-Terra Olymp-Aqua DeepS-Aqua DeepS-Ventus DisneyT-Terra DisneyT-Aqua. Neverland and DestinyI simply in order of arrival. For the final battle I'd say Terra,Ventus,Aqua.