Sora had Riku's keyblade for the majority of KH1 and that didn't stop him from summoning it like any old KW does. It seems like this whole Keyblade choosing thing is a bit overrated.I don't think DP would be Kairi's permanent Keyblade because it was just given to her, she wasn't chosen by one that was forged from her own power like how Mickey was given SS Yensid's keyblade, but was chosen by KKD, his own personal Keyblade. Since Kairi's an important character I doubt they'll have her be the only member of the two main trios that was just given a Keyblade rather than gaining her own.