Still chewing on this. Here are some additional thoughts.
Speed sensor
I don’t really suspect that I need to replace the magnet, as I don’t get an error code until I hit the pedal.
This was a guess. We might still need to come back to this.
Agreed, I have always associated -82 being more associated with the sensor and not the magnet.
I DO find it odd that rolling the car For/Back 10 feet does not generate enough signal to trigger a number change on the display. (usually it does). Checking the green wire from the sensor might see some movement on a digital meter but difficult to predict.
Note - If you are rolling the wheel with both tires up in the air, then most likely the other wheel is going in the other direction as you are spinning the first wheel. This is the nature of how your gearbox/differential works and more suitable for another thread.
Mentioned here because if the other wheel is spinning, the motor is probably not(or very much). I think you noticed this with your comment here.
I also noted that the motor only spins when there is torque, so once the wheels are spinning steady, the magnet doesn’t spin and I have stop and spin again to get the motor to spin,
If you want to observe this, Have someone hold the other wheel or block in in some way that keeps it from soinning (possibly leave it on the ground?
-11 Pedal Error
I am leaning more towards something is dodgy in this controller.
From what I can tell from your descriptions, the pedal switch is functioning correctly. Even you test on P3 looks normal.
Random thought of the day
Maybe this is a controller input power issue?
Way back in the beginning of this post I had you fully remove the controller lid for inspection. You had it back together before I could get you to clean the internal pad connections for the Pos and Neg cables (they looked a little messy). We might need to make sure these are cleaned later, but for now → make sure these connections on top of the controller are a bit more than snug tight.
A known point of point of failure is sometimes the flippy breaker on the front of the PSDM. Make a small jumper wire and go across the two connection points as a test.
Another point of fail might also be the twin B- wires on the front of the PSDM (right side). Look at them close for any signs of heat(like a melted case where the studs exit below the cable lug and bolt fastens. As a test → Jump across those two studs (momentarily hold a wire across if you want) and see if that gets you past the -11 at pedal press.
Let us not forget the Pack
It might also be a good idea to go though all of your battery connections and look for loose, corroded, fuzzy, melted, rusty, discolored, or otherwise dodgy connections back there.
Clean, Bright and Tight is the rule.