Backup and restore is not an option in this case. We cannot get any data from your existing first gen IQ Panel, it cannot be activated on an account due to 3G cut-offs.
If we choose panel 4, can the existing window sensors be added by opening and closing the window or need to bring the sensor close to the panel for re-programming?
Alarm sensors do not need to be brought close to the panel. You can open the sensors to pair them while the panel is in auto-learn sensor mode.