In your current configuration, the port used on your Pixhawk for FrSky telemetry is configured to use the legacy protocol, which is why you get these sensor names.
You must configure the port used on your Pixhawk for FrSky telemetry using Craft and Theory’s protocol, which sends more data than the legacy protocol and in a more optimized fashion. For example. if plugged into SERIAL 4/5, set SERIAL4_PROTOCOL to 10 using Mission Planner, as shown on page 6 of v2.0 of the manual.
Then, discover the sensors again. Sensor names such as “1000” should be discovered.