Does the Freefly RTK GPS work on other, non-Freefly aircraft?

Yes, the Freefly RTK GPS can be used with other aircraft and autopilots, as long as they support the comms buses (I2C, serial) and devices (ZED-F9P, IST8310 Mag, etc…).

For PX4-based aircraft, please note that you will need PX4 1.9 and later for the UBlox F9P drivers.