You need to remove the # (Hash) from the Audio Inject entry, as this usually signifies the entry is to be ignored.
Have you been using #Inject when testing the other layout ID's? If yes, you might want to go back and re-test tthem. As none of them will have been injected! If the <key> element is to be ignored, so will the <string> .
You should't need to add VoodooHDA=true to the config.plist, simply remove AppleALC.kext and run the VoodooHDA installer if you are installing VoodHDA to /Library/Extensions, or copy it to /CLVOER/kexts/Other folder if you are loading it from your EFI folder.
Personally I would test the layout Id's with AppleALC.kext before switching to VoodooHDA.
I think your Linux experience is adding to your problems. While the two OS's are similar, macOS does not use a lot of the Linux configuration settings. If you have added the # key to any of the other entries in your config.plist, I would recommend you remove them too.