It showed on the screenshots the gameplay is both Sora and Riku , so who would you play as first?

Riku, duh..... Everybody likes Riku more than Sora, except maybe people that have Sora in their names

Sora. He's just so adorable!

"And then we can go see Santa!" (I know it's not from the same game, but still. So cute!)

Just because that the game shows Sora and Riku, doesn't mean that you have the option to play as one of them first. It could be that the game starts off as playing as Sora, then you play as Riku, and so on and sou fourth

according to nomura, you switch characters through the game, like, you play a little as sora, than as Rik, then as Sora, etc etc etc.... so there really isn't an option.

according to nomura, you switch characters through the game, like, you play a little as sora, than as Rik, then as Sora, etc etc etc.... so there really isn't an option.

 

now that i would enjoy

according to nomura, you switch characters through the game, like, you play a little as sora, than as Rik, then as Sora, etc etc etc.... so there really isn't an option.

 

How would character development occur then? Would each character have their own abilities and customization saved separately, or would they have the same growth, abilities and equipment?

Well...I did see somewhere that SE(Square Enix) said something bout having Sora and Riku twitch back and forth between the gameplay. But the games still being made, so maybe there change theres minds or something:p. If I "cloud" pick, I'd choose Sora. Never really liked playing as Riku very much...From the past the games, I thought Sora was better:3

I'd play as Riku. Reason? Cuz I wanted to play as him for a change

You don't choose which of the two to play as like in CoM. You alternate back and forth between the two at certain points in the game.

You actually alternate between Sora and Riku.

As far as we can tell, mind you.

It could be something else entirely, especially given Nomura's inherent crypticness.