When Kairi lost her heart it went inside of Sora. But this didn't create Namine. Namine couldn't have a body, so when Sora released his heart, she was then created. She is made of Kairi's soul, which is made entirely of light, and Sora's body. Later, Xion was created in order to speed up the release of Kingdom Hearts, and to keep Sora from awakening. To do this, Vexen made her a replica of Sora from his memories of Kairi. This makes Xion the Kairi Sora remembered after he woke up. Because Namine is part of Sora as well as Namine, they are connected through Sora AND Kairi. Xion is connected to Kairi because she is the memories of Kairi Sora possesses.
This is my new theory!
When Kairi lost her heart it went inside of Sora. But this didn't create Namine. Namine couldn't have a body, so when Sora released his heart, she was then created. She is made of Kairi's soul, which is made entirely of light, and Sora's body. Later, Xion was created in order to speed up the release of Kingdom Hearts, and to keep Sora from awakening. To do this, Vexen made her a replica of Sora from his memories of Kairi. This makes Xion the Kairi Sora remembered after he woke up. Because Namine is part of Sora as well as Namine, they are connected through Sora AND Kairi. Xion is connected to Kairi because she is the memories of Kairi Sora possesses.
I hope this one doesn't backfire...