1 - Yes, if it works the same way it does in 6D and 7D series bodies.
2 - Never tried it, but I would not expect it to work. They made a fundamental change to how consumer GPS devices work several years ago. If your velocity exceeds a certain limit, then the GPS no longer locks onto a satellite. This was done to limit the ability to use consumer gear to guide missiles.
3 - I am not sure if the built-in GPS records altitude or direction. Try it with a cell phone or camera, and see what happens. As I noted above, I would not expect it to able to maintain a lock on a satellite.
1, Got it.
2. I'm taking my first flight since COVID in Late August. If I remember to, I'll report back.
3. I know some GPS devices do report altitude. My Canon GP-E2 that I used on my old T5i recorded Altitude and the direction the device was facing.
I learned that I can use Adobe After Effects to do what I want to do if I have a good log file. I bought a telementry template from someone who made meters for all types of movements,
Per question 3 - regulations place a limit on GPS tracking devices that disables tracking when it determines that it is moving faster than 1,000 knots, and at an altitude higher than 18,000m. Some manufacturers interpret this requirement as an or function, which means that it stops working at altitudes above 18,000m.