Today, I was able connect SITL and MAVProxy on one laptop (running Debian 10) to a Windows 10 laptop running X-Plane 11 (with a Taranis X9D+ as a joystick) for it’s flight dynamics and Mission Planner or QGroundControl as my GCS. The laptops were connected over ethernet. Worked pretty slick.
I’ll document my setup in an ArduPilot Blog post soon.