So I got the Mayflash adapter and it works great - my Wii U 3rd party controllers pair instantly and I can pair up to 4 in Dinput mode without issue.
However in Dinput mode I can't program the Home button (as a Hotkey) in the controller setup. When it comes time to program it it just doesn't work. It does work in Xinput mode, but then I can only pair one controller.
Currently I'm using button 10 (left analog stick push switch) as the hotkey, but this is less than ideal. Any suggestions? Thanks!