That's a neat theory. Nicely put together.

The only thing I could disagree on is the fact of it being several hundred years later. You'd need thousands, perhaps millions of years to get that kind of continental drift going on, unless of course in this world continental drift is happening at an incredibally rapid pace, which would mean very fast tectonic activity, and inherently a lot of volcanic activity going on. Though it is Final Fantasy, after all . Perhaps this is the same world, but hundreds of thousands years later.

Everything else ties together very well, with the Sorceror named Hyne, and the reference of Ultimecia's clock tower.

Very interesting.