About the only thing you can do is run your monitor at a lower resolution.
That's up to the aircraft developer, and as the Saab has seen free updates from 2013 to now, there are no further plans to make updates.
The next major version of the Saab 340A will have the new window system, but this is not slated to be a free update, and it's not slated for release anytime soon.
No, this is not possible. The legacy X-Plane window code was not capable of detaching from the sim to pop out on other monitors.