I just made the change suggested and am using the IP address associated with the Ethernet. Unfortunately it didn't work. What happens is the functionality of the mouse stops working immediately when the 2nd screen appears. The only way I am able to disconnect the WiFi displays session is by using the touch screen.
I'm not sure what info I can provide to make it more clear, as you stated "its difficult to follow exactly what you are doing". I tried to be very clear and detailed in my original description of the problem. Please let me know what else you may need to be able to recreate this issue on your end.
The issue, that the cursor works but will not interact with the desktop (if that is indeed what you are seeing), reads like this, and its fix:
Stardock Support Manager