In v0.1.3 of the Vulcan, we upgraded the GPS from the Aera GPS to the G3X Touch for better MSFS 2024 compatibility. Therefore, the functionality of the GPS has changed slightly as the G3X Touch is a more advanced GPS. To cover each of your points:
If a flight plan is created in the MSFS 2024 EFB, the "Send Route To Avionics" button must be pressed in order to import the route into the GPS. If a flight plan is created manually within the GPS, the flight plan must have a departure airport and a destination airport set in order for the autopilot to couple with the GPS (if a flight plan is created in the GPS with only a departure airport and waypoints, the route will be displayed, but the autopilot coupling will not function with an incomplete flight plan). In order for the autopilot to track the GPS flight plan, the ENGAGE knob must be pulled (with IN indicator showing white), the TRACK knob must be pulled, and REMOTE must be selected on the navigational selector.
This is a known side effect of a workaround we have put in place to improve touchscreen display interactions in our aircraft in MSFS 2024. If the workaround is no longer required after future MSFS 2024 Sim Updates, we will update the logic so that control cannot be clicked through touchscreen displays. The GPS can also be moved on top of the glareshield by clicking the upper bezel.
As the G3X Touch is a default GPS unit in MSFS 2024 (developed by Working Title), we sadly don't have any control over the scaling of the GPS. To circumvent this, we have added custom cameras for each GPS position which moves the camera closer to the GPS display. These cameras can be toggled either via the MSFS Camera menu, or via a clickspot on the right bezel of the GPS.
Mark - Just Flight