I wanted to throw out another possible chapter breakdown and describe a structure that I'm calling a "runup".
In Rebirth's reveal trailer, the compass on the top of the screen states that the next objective is about 1060 meters away. This is a decent distance. We also get a glimpse of the field size. We don't know precisely what the destination is, it could be Nibelheim itself or some other point of interest along the way, but the scene gives the impression that the field of exploration will be
wide and
deep.
I think a lot of chapters will be structured this way. Rebirth will not be an open world game. The plot isn't made for it, there's too many locales to cover. Instead, I think the world will be portrayed through wide hallways leading up to each town. I call these "runups". They allow players to explore the region a bit before finally revealing the town itself, the cultural center.
With these runups in mind, here's how I'd structure Rebirth. The blue boxes represent linear chapters, like what we got in Remake. The orange circles represent chapters with runups. In chapter 3, the runup would begin at Kalm and end at the Chocobo Farm. In Chapter 5, the runup would begin in the wilderness and end at Under Junon, etc. Quick side note: Chapter 15 would include the Gold Saucer revisit.
And here's everything that would be pushed to Part 3:
Fort Condor
Gongaga
Wutai
Bone Village / Sleeping Forest
Most of these are optional to begin with. In Gongaga's case, it may be better to visit once we have a clearer picture of the Zack situation. Bone Village and the Sleeping Forest are cool, but let's be real, they aren't essential to the plot. If we gotta move something, best to move something that doesn't directly relate to any character's backstory.