In all fairness Xion herself doesn't need to have a connection to Lea as long as Lea has a connection to her (whether or not he's aware of it). Like HPO feeling like they're friends with Roxas even though they don't know him, the chains of memories are connected. That's how the Rinzler stuff works too, Sora recognizes him because he knows Copy Tron, and that's enough for Rinzler to feel connected to him. I think that's kinda explained in coded via Donald and Goofy re: Data Sora. But it is confusing.
Lea didn't seem to feel connected to the Xion copy at all though. We see, on screen, that he only remembered Xion and started talking to her with familiarity
after the original returned. Prior to that, Lea and Kairi were just fighting her for the sake of it. The identity didn't matter.
HPO based their feelings on Roxas around a picture taken from the digital Twilight Town. They were aware that a different version of themselves were friends with Roxas (I think Goofy even suggest it outright). In other words, they needed to have some kind of strong emotional prompting.
Donald and Goofy had to befriend Data Sora all over again throughout Re: Coded. It wasn't a matter of automatically being connected to him through the other Sora, even if they did compare the two.
All that said, yeah, I agree with the whole Rinzler scene.
Honestly it'd make more sense for Xionort to be a new replica recreating the original Xion based on data collected.
Mmmm, this is getting old. Does anyone remember how KH2 and Re: Coded made a big deal about "hearts being more than any system"? Part of the message of those games is that you can't just make a heart from Data alone, it has to form bonds and have strong connections to the people and world around it. Data Sora had to
earn his heart, for example, he didn't just start out with one. That's not how it works.
Anyway, I still don't get the logic behind the whole data explanation either. Whatever info Vexen would've had on Xion could not have included her weilding a Keyblade, or looking like the black haired Kairi we all know and love. All that was said, by Xemnas, to be the work of Sora himself, and it only occurred after Vexen left for C.O. Where are they getting this data from?