Quick update: I have everything working now (I think)... Except for audio!
I used your latest EFI, as I didn't have any port limit patches in my config.plist to disable... I probably did something wrong at some point! Once your EFI was in, I can see your port limit patches and they're disabled. So all the USB ports are working now - aside from the USB type C, and the port directly above it, which is expected with your SSDT. I think in future I'd like to get those two working, and can presumably swap out something else like the RGBs, as you've mentioned before.
I got the graphics glitches again, so I did what I did before and changed the SMBIOS back to iMac(14,2) using MultiBeast, and that fixed it. I used Intel Power Gadget to verify hardware acceleration was working, using this post, and everything looked fine (on my i7-8700, HD630).
Interesting point about audio not working with the integrated graphics enabled. I have the common issue of no audio devices detected at all, but my two folders (EFI/Clover/kexts/Other and System/Library/Extensions) look identical to yours, aside from missing a couple of unrelated kexts you have.
I've read a few posts about the audio, such as this, but don't really understand what I'm doing with it. Also I note that's for AppleHDA, and I have AppleALC.kext . . . I don't understand the difference!
I appear to have Bluetooth, but I've read somewhere on here (can't recall which thread) that someone had to boot into Ubuntu or something, to initialise the Bluetooth card, as the address was showing as 00:00:00:00:00 - it's doing that for me. But I'd rather just get a replacement card that works perfectly with everything!
Thats great news. More good news is that I'd lost my audio too while messing about with the iGPU. Even after a time machine restore.
I used this guide found here. Go to the Audio section. Take your time reading it. I must of read it several times myself. At the end of thread it will show the issues Ive had (page 17-ish). if you have/don't AppleALC.kext or Lilu.kext install/upgrade them into Library/Extensions using KextBeast.
My audio config as the recommended method 2.
Audio should work (hopefully).
I followed that guide to enable a headless IGPU and now I have HW acceleration for whatever real Macs do with it.
USB type c is up to you but I still got 2 other gen 2 ports which is at 10gbps. I really don't know what hardware would utilise it. Remember we have a spare NVME port for extra storage anyway!!!
As for my wifi&bluetooth it just worked after I did what I mentioned earlier in this thread.
If your going to stick with IGPU, I would follow the rest of that guide and use whatevergreen.
Are you saying that you're using the card that came with the motherboard? For some reason I had it in my head that this model only half works with macOS... Am I wrong? I'll check the chip number on it later, don't think I ever tried the Broadcom kexts for it.
Thanks for the info on audio - I'll have a good read of that thread tonight. Excited that you've got it working with the IGPU! I definitely have AppleALC.kext and Lilu.kext, but I've read somewhere else about them perhaps not being the latest versions.
Yeah, with the USB type C, I guess I'd just like to have a completely working system. My phone is USB C but I have a handful of A -> C cables so it wouldn't matter anyway. Think it's still USB 2.0 speeds as well. I'll maybe get around to making my own SSDT at some point.
I replaced the card that came with the MB with "Broadcom BCM94352Z". To get wifi and bluetooth working, see my networking section.
Hopefully I've I given enough information to get the audio working without too much of a headache but if you do get stuck then I should be able to help.
I might enable my usb c at some point if I ever have some hardware that requires it but I doubt it as its a desktop and I've only seen one usb 3.1 gen 2 hub on the market so far and that's type A anyway.
Also using that FB-patcher, you can create your own usb.kext which means the custom usb.aml and usbinjectall.kext can be removed.