I'm trying to run Mojave on my M6800 (specs in signature), and I've run into roadblocks:
1. Dock's USB ports don't do anything. Wasn't an issue in Sierra. Fixed by using my old DSDT and SSDT.
2. When booting, I'm getting "Unsupported CPU", followed by "Unsupported PCH", followed by 4 60 second timeouts from AppleACPICPU.
3. When booting for first setup or after upgrade (tried clean install and upgrade), I'm greeted either by zero output, or no display but backlight on internal screen and no signal on external displays when nv_disable=1 is set. Now I get a black screen with a cursor, and when I press any key the screen flashes.
Have tried a known working ESP from Sierra and your ESP, neither booting past this black screen. I've also tried using Whatevergreen to no avail either.