I have a really big problems with things like those. The game can only end with a cliff hanger and we don't know if square will create part 2, 3 (well how many there should be, I don't know). If the game is not a success square won't create the next part.
And if they create the next part, it can take years before it gets released.
Well, I will only buy it in a complete form and if it really delivers a FF7 like experience. So maybe in a few years on next next gen hardware ^^.
What about games planned to be a three part story from the start, such as Mass Effect?
All Mass Effect games (well except for Andromeda) had a satisfying ending which end the story part of the game without big cliff hangers. Yes, there was always the "someday they will come back"-situation but the main story of every game ends with each game.
-1: One Reaper ship ... is defeated
-2: One reaper operation base ... is defeated
-3: All reapers .... well defeated (more or less)
Here we have a remake of a game where we already know how the story ends. Maybe they change some details in between, but that is all.
I really hope they don't do it the FF XV way ... horrible game, story and characters, even with the addons