You've lost me on item number 2. How is the RPi connected to the local eithernet network?
Are you setting the IP of the Stratux box to a static IP on your LAN and connecting the stratux to the LAN via Wifi?
I currently connect via WiFi from my Desktop to the Straux, same as I would sitting in the airplane.
Also connected via Eithernet to the home network at the same time. Never had an issue. Windows 10.
But your solution is sounds interesting.