No, believe it or not we just have different perspectives on things.
After all this evidence, I"m much more inclined to go with your theory like I was in the past. Now I just have to connect the dots about Namine at the same time though.
But HeartSeams, try to understand that people have different speculations about things. Everyone, probably you even, thought that Vanitas would have Riku's face or something like that. But I"m dead sure NOBODY on this site thought he'd have Sora's face.
And just because something has a lot of evidence doesn't make it fact. I'm certain that if anyone said Vanitas would have Sora's face, that person would have be verbally ripped apart by you and other people on this site.
Even though it was just a theory though, Vanitas having Riku's face would have made more sense at the time considering nobody knew about Ven and Vanitas's connection. Even him being Xehanort made sense since the face was never shown, despite Terra looking similar to Xemnas.