How would it be Sora, Kiari, and Riku? If it were them, why would they be dressed up in knight's outfits? Why would there be "In memory of Xenahort" on the screen if he was that evil Ansem thing??? Also, why would there be all of those keyblades in the ground? And finally, why would they be in a desert?
Although I guess it is kinda possible that one of them is female due to the way she walks, and the height of the knights would definetly hint them as being Riku, Sora and Kiari...
My head hurts...