Ok, so we are back - up and running. I followed your suggestion. Now what do you want me to do for the multi-monitor issue? Thank you!
Just to confirm... You have copied the EFI folder from post #1275 to the EFI partition of your main system drive, correct?
If yes, leave that as-is until we figure out why you are getting black screen and why you are not getting acceleration and multi-monitor support. Just use your USB flash drive for testing until all issues are resolved. When it is, you can replace the EFI folder on your system drive with the one from your USB flash drive.
On Mojave, once you have IGPU enabled in BIOS with 64MB or more, we should be able to leave config.plist > Graphics and config.plist > Devices > Properties empty and Clover/macOS should be able to detect your IGPU and automatically use them correctly.
On your original config.plist, you used a fake device-id for your IGPU. This gives video but no acceleration at all. The first thing I did was remove this fake device-id.
In the past, we needed AGDP fixes to correct the black screen issue that affected Skylake systems but WhateverGreen should have fixed that... Another thing that can cause black screen is incorrect connectors being used. If this is your problem, you will need to patch your Framebuffer using the following guide:
General Framebuffer Patching Guide using Hackintool Please do not quote this guide in its entirety. Post a link instead. 15 Jan 2019: Intel FB-Patcher has been renamed to Hackintool. 19 Jan 2019: Guide overhauled. Please be aware of possible HDMI hot-plug issues. After boot you may have to...
www.tonymacx86.com
Edit:
One other thing worth trying is to use iMac18,1 system definition. Since both iMac17,1 and iMac18,x use Z170 chipsets, there shouldn't be any issues.