hrm... guess they took Rise's concept and turned her into Ai.

No, I think they've just got concepts for two different characters on the same page. They'd have the personality by they time they're doing the sketches, and the Rise sketches are just too upbeat to be Rise.

text from the P4 Visual Data book does say this whole page was initial designs for Rise, but the wavy hair was finalized into Ai's character.