Switch is fine. Checked and double checked. When I get a chance this Summer I'll examine the code and see if I can figure out what is going on with the service and hardware. Any suggestions on where to start?
If you are interested in working on the ControlBlock sources, a place to add that functionality would be https://github.com/petrockblog/ControlBlockService2/blob/master/src/controlblock/SNESGamepad.cpp. You could take a look at https://github.com/petrockblog/ControlBlockService2/blob/master/src/controlblock/MAMEGamepad.cpp, where a simulated keyboard is already implemented.
The ControlBlock emulates two individual gamepads on your system. If you connect any additional USB controller it will simply show as another controller that is attached to your system.
So, there is no problem with having arcade controls together with any additional USB controller.
Contributions to the project are always appreciated, so if you would like to support us with a donation you can do so here.