If they would've done Fantastic Beasts, then why in the seven plains would they want to replace Twister with something like The Tonight Show?
The London we see in USF, is the Harry Potter's London. And I would be damned if they can get away with the prospect of a Fantastic Beasts New York, right next to an already existing New York land.
I think the only thing you'd see added for the north, is the Ministry of Magic, and that, they would try to keep it close to the timeline's of when Gringott's and the Diagon Alley "land" exists.
I think, if they do Fantastic Beasts, it'd probably be with the new land, and that it'd be "Fantastic Beasts _Fill City Here_" and not "_Fill City Here, and have FB isolated_".