I see that you had an excellent support from Dr. Hall @Leonardthall , I suspect we might not have better qualified resources to help you on this issue. I suggest you get more acquainted with ArduPilot methods as they differ greatly from PX4.
And his conclusions are:
This is clearly not an ArduCopter problem, an ArduCopter tuning problem or a problem with the PR. Mavros is commanding the aircraft to crash and the aircraft is then doing what it is told to do.
The only thing that makes sense looking at this is that mavros is commanding the rates in degrees per second instead of radians.
This is completly the wrong thing to do. The problem is not there and you are just blindly trying things hoping it works. In any case mate, I am satisfied that this is not a problem with ArduCopter and that the problem is with mavros or the settings you are using there.