Half those symbols I can't figure out. First thing this KH chess set needs to do is tell who is who. None of these symbols look like Dark Riku. Yet there is one that looks like Vexen's who wasn't even in the war. So confusing lol.
Correct, but notice, as we were kinda getting at, the Roxas, Axel, and Xion symbols aren't included on this art piece, and did not show up in-game.
As for the ones that *are* included, here's what we have:
On the Light set, from left to right: Sora, Riku, Kairi, Mickey, Terra, Aqua, Ventus
On the Dark set, likewise: Master Xehanort, Ansem, Xemnas, Xigbar, Saix, Yong Xehanort, Marluxia, Vanitas, Larxene, Demyx*, Vexen*, Luxord, Riku Replica*
*Note: These three asterisked I am not totally certain of, but seem within reason and the best possible guesses; the rest of them I am pretty much certain of, and can dig up reasoning and evidence to support them if need be