Popular thinking at the moment is that 6* units cannot come out until Dirnado is fully released (this was the way it was on JP). So, Gumi, is currently throwing every banner that they ever created that does not contain 6* units at Global currently.
Dirnado Part 2 is still 3 weeks away, which pretty much dictates the exact three banners Valentus is discussing (FFCD, Facebook PC, BF), because there is no other banner/event that has ever existed in JP that does not contain 6* units after these collabs.
So, expect Lightning, FFT, and other 6* unit collabs to come locked and loaded at warp speed in very early October. The only question is which 6* unit comes first, as Global's director has said that they are seriously considering reordering the releases of 6* units from JP. (My money is on either FF4 or FFT going first, with the other going second. Lightning is not much of a draw in the West, compared to Japan.)