Plot-related question: given that a) the segment would play in between the original game, b) the data being worked on are supposedly coming from old files and c) Vexen not being mentioned translates to him not being directly involved, how would Cid be supposed to extract informations about those member from the Real Organization XIII whose identities neither Ansem the Wise (for obvious chronological reasons), Sora or the others have no clue about? Because, as far as I remember, the trio does not actually meet them all (e.g. Terra-Xehanort, or Xion) prior to the final segment at the Keybalde Graveyard.
A great question that I sadly don't have a satisfying answer for LOL My best guess is that around this time, Ienzo would've found some encrypted data before Vexen came back to him and Ansem to go mask-off as a double agent to the SoDs, and all of that data would be to keep track of who in the new Org was using replicas, etc, etc. And so to get around the encryption, Ienzo would've then passed it off to Cid. Like I said, not a great fix, but maybe sometimes minor plot-holes are necessary to necessitate post-game content. Kinda like how KH2FM's Garden of Assemblage was 👀
Not sure how much sense this makes but the best I could come up with is: After regaining his memories and banishing Ansem the Wise, but before splitting himself into Ansem and Xemnas, Apprentice Xehanort was given a visit by Young Xehanort through time travel and given a rundown/reminder of the whole plan, including descriptions of the future Org members and what they're capable of. He put all this info into the computer in Radiant Garden and now 11 years later the restoration crew managed to unearth that data. As for how this would be explained? Uhh put them in a secret report and you're good.
Hmm... if I could make a suggestion, I feel like Sephiroth shouldn't be unlocked by beating the Data fights since he was always easier than the Xehanort superbosses in KH1 and KH2. That said, I do like the idea of Cid scanning Sora's data (or just using Data Sora from Re:Coded) to handle the Organization after the plot of KH3 concludes before leading into a fight with Sephiroth.
Honestly rewriting kh3 isn’t that hard all the game needed was a story, a good plot, less meta humor, more narrative cohesion, less fan service, being a good game in general. So you know not too much 👀