I've tried adding device HDAU and fully populating GFX0 (DSDT_HDMI11 and DSDT_HDMI12), both DSDTs attached.
Would the AppleALC layout ID I'm using (28/1C) cause any issues?
HDMI Audio was working under Lion using VoodooHDA, after updating to Sierra the VoodooHDA I was using no longer worked. I tried updating to the newest revision and same thing.
The edited dsdt has all audio devices defined correctly. DSDT/HDEF is not working. Problems are noted above.
Verify there is not another EFI partition Clover is using to boot.