They are making at least 3 episodes so it stands to reason they'd have to start ramping up just to keep the second and third parts going , especially given the easy assumption that Midgaar makes up all of the first entry. After that a big map will be expected and tons of different textures / models, etc. So going on a hiring spree would be a good thing.
Even if this is just for episode 1 and that game has only finished it's first proper playable prototype , square have shown they only need 18 months to have a finished game once they go into super crunch.
Thing is though.... I've long expected that Kingdom Hearts 3 will take priority over this remake project. It was started 2 years prior to FF7R afterall and this E3 will mark at least 4 full years of production. 2018 will be it's year. Then, probably late 2018 or early 2019 for the first part of FF7 , ideally with the rest following 18 and 36 months later respectively. Finally, a deluxe "full" release available on PS5 after that.