VI - Could you please give an explanation for the new keyblade "Way to the Dawn" that Riku obtained and the keyblade Kairi has as well as what the conditions for using a keyblade are?
There isn't necessarily one keyblade for the dark side and one for the light side, just as many as there exist people with qualified hearts. Concerning the conditions to wield one, at this stage, "Those with strong hearts" is the only obvious one. However, less obvious conditions still exist and there are still plans for an opportunity to reveal those. Riku's "Way to the Dawn" and Kairi's keyblade are naturally the same type of keyblade as Sora's. However there is no particular explanation for the Soul Eater's transfer and occurrence, as well as Riku's handing it to Kairi. When there isn't a normal process of acquisition, I think its ok to think there is some deeper meaning there.