Nobodies are half a person so while Roxas and Sora were separate they still retained the other's strength.

Xion was what happened when you run out of toner.

Ansem states that Naminé is a new thing altogheter as She does not have Darkness or the body and soul of Kairi she is mostly made of "nothing" besides probably the links of Sora's relationships.

Good video.. although I think KH 2.5 will be out before KH III

Doubtful. Roxas may have been created when Sora turned into a Heartless, but you have to remember that Roxas looks exactly like Ventus, whose heart took sanctuary within Sora. It stands to reason that Roxas is in actuality Ventus and not necessarily Sora's Nobody. This can be further proven with the other Nobodies who still look like they did when they were Somebodies, while Roxas looks nothing like Sora.

With Kairi and Naminé...seeing as how Naminé is Sora and Kairi's "child", being born from his body and soul and her heart, it's also doubtful that Kairi had "half a soul".

Well you're kinda right. Roxas looks like Ventus because that part of his heart took Ven's form which as you said, is resting within Sora's heart to mend. However, Roxas and Ventus are two completely different people with two completely different personalities. Also since Sora was a nobody for such a short period of time, all of his memories didn't go completely to Roxas. That's why he was such a zombie at first and didn't remember anything from his past. But you also have to think: Yen sid said that when a person turns into a Heartless, the body and Will are left to wither away. But if their heart was strong enough they would combine to form a Nobody which is basically their body and their will (their soul). But like I said, Sora was a Heartless for such a short period of time that Roxas never had the chance to fully obtain all of his memories which made him a zombie at first. So all I'm suggesting is that a part of Sora's soul rests within Roxas and the same with Kairi and Namine while they exist simultaneously.

Sweet. Will watch when I have time. (Previously discussed loss of full time internet combined with the videos length = no time for a while....)

This timeline's great, I learned stuff, I didn't even know existed nor questioned.

I'm kinda disappointed that they didn't go into how the secret bosses allude to future events of the series. The Unkonwn in Hollow Bastion hints towards Xemnas in KHII, Lingering Will hints towards BBS, and BBS' Young Xehanort fight that hints towards DDD.