Hi there
I have the same motherboard and nearly the same other hardware, and I followed your installation but I cannot make my audio work. I have used Sierra 12.12.5. Furthermore I connected my monitor LG 27UD 58 with the DisplayPort cable I hope this is not the problem.
Update: I have my audio work, my only problem is to get my Thunderbolt 3 working. I have tried the procedure with Windows, and in Windows I see my Thunderbolt drives and can see all the drives and files. But, after I shutdown Windows and start Sierra with connected 5 bay array, I get the message in my System under Thunderbolt no drivers loaded. I use a Apple cable from Thunderbolt3 to Thunderbolt 2, and I use a 5 bay array from Oyen Digital.
I have updated my bios to f20 and I also add my config.plist and a pdf file with screenshots of my bios settings.
Thanks for all your work and good description from the procedure.
If you need more information for me to help, let me know.