Regarding the "unacceptable" FreeSync range, are you worried about the upper or lower limit? Usually the lower limit SHOULDN'T be an issue because of the LFC. Because if the game is operating at 30fps, it can multiple the framerate to reach 90Hz, which falls under the range.
But I also noticed a small discrepancy in the range setup, which I am actually slightly worried about: the 60-80fps range would apparently fall outside FreeSync operation, as it isn't directly inside the FS range, and can't be multiplied to it, either. I just find it hard to believe that the R&D personnel would have let something as simple as this pass through the design phase... Before purchasing a monitor with such a range, you should probably consult the manufacturer, first.
Actually, I thought LFC required the range maximum to be at least 2.5x the range minimum. And 2.5 x 80 would be 200Hz, so something doesn't add up. Well, technically 2x is the bare minimum, and 0.5x is just a buffer. But 2x 80 would still be 160Hz, so even that is not enough. Anyway, searched around, and found this discussion thread, if anyone is interested:
https://www.reddit.com/r/Amd/comments/5cv2kj/does_lfc_freesync_support_still_require_that_the/
But it doesn't seem like they've found any explanation to this.