The answer will be 'we won't decide until Part 2'. Part 1 is going to be purely Midgar. I'm almost sure of it.
I bet the overworld ends up pretty similar to the original. A scale version of the world your characters run around on, only a bit prettier. Maybe put encounters on the Overworld instead of random battles as well.
Oh, I agree that Part 1 will be just Midgar.
And the problem with your vision is that to do that, they'd need to either lock off portions, or make all towns visitable.
That's not hard until you get the airship, but once you get the airship...
I honestly expect that they're going to linearize it, and make it like FFX as many suspect.
i mean if we want to go straight into spoiler territory for a near 20 year old game then lets do it.
pretty sure that almost all of cloud's memories are Zack's and zack is the man now, dawg. Cloud is just a fake, a loser, a dude who basically pretends to be zack and steals his cool cool backstory and makes it his own.
Cloud actually has all his memories, plus possibly some of Zack's.
There's definitely still Cloud in there, given that he remembers growing up with Tifa and the like, as well as what really happened in their hometown when he came back. If it was just Zack, he'd know Aeris and barely remember Tifa.