I think we have reached the point of no return as far as talking about the next gen Z.
But as far as the BRZ goes. Where do you get that it is speculation? Unless all the news outlets are trolling the BRZ/FRS platform stating they are getting turbo/supercharged treatments respectively. Multiple sources are stating that both Toyota and Subaru confirm that it is in the works.
Subaru confirms turbocharged version of BRZ engine - Top Speed