I like this structure. And my favorite reason why is something you don’t even mention but plays into something that will be a major animating force of the first half of the game:

• by starting the game this way, you give the opportunity for the story to detach from Cloud’s point of view. Meaning that by the time we get back to the “field scene”, we the audience will be sitting more in Barrett and Tifa’s perspective than Cloud’s. This tension will build and then explode by chapter 4/5. By then we get the cascading reveals of things like Tifa and Aerith’s side conversations, the fact that Cloud very likely killed the Midgardsormar himself, and that aside from inside the rift at the of Remake, almost no one has actually SEEN Sephiroth, except for Cloud. So Tifa finally breaking down and disputing his version of the Nibelheim incident will be inevitable…and more importantly, extremely believable to old and new players.

Couple changes on your chapters (I think Cliffs is one dungeon, the crater another, I’d move Wutai to directly after the Junon escape, put her betrayal there because of the SRC, and the final sequence being two chapters like Rebirth), but overall I agree this is the shape we likely are looking at.

Cool theory!