It looks like Fusion's own controls don't function with exported Mac apps and from what I can tell none of the existing gamepad extensions support Mac exports either.
(If I'm wrong I'll be happy to be directed in the right direction)

So I would really love to see a new gamepad/joystick/Xbox One wireless control extension that does support Mac apps created with Fusion. Or an update to an existing extension to add support for Mac apps.
I'm happy to do any testing that may be required for anyone who does not have access to a Mac themselves. Or if I can help any other way to bring this about, please reply here or contact me.

If you are reading this, thanks for taking the time to do so.