Guess what. I fixed the QE problem just now! I had to use 0x16268086 as Fake GPU ID in config.plist/Devices/IntelGFX. I now have full acceleration (finally after 2+ years of struggling), and HDMI also works now after resolving the issue with QE/CI. However, this fix doesn't work on Sierra and no idea if it works on High Sierra until I try tomorrow. Perphaps Apple changed something in AppleIntelBDWGraphics.kext on Mojave? The mystery is, why does my IGPU require a Fake ID in order to get QE/CI acceleration working, when I see others with the same CPU having no issues with that...