My predictions of a Final Fantasy XVI are:
1. It won't release this generation I'm thinking they will try to get what they can out of the previous Final Fantasies like the 7 Remake, XV(whether this means DLC, Kingslaive game, Versus XV, or a XV-2 remains to be seen), X-3, and whatever spin-offs they can produce for the PS4/XBOX/PC/NS
2. It will be an action RPG similar to well selling Final Fantasy XV
3. It will be turned into a trilogy similar to FFXIII, and FF7 Remake?
4. It will use Luminous Engine, as they have probably been working on something called Luminous Studios Pro?