Glad you made some progress here - no reason to leave so many out of the fun.
I haven't seen a kickdown / throttle constant, but that doesn't mean it doesn't exist. I wouldn't be surprised if the throttle position is broadcast over CAN - torque definitely is (for DSC). I never looked to be honest.
In the case of MSx70 and MSx80, there's no 3D throttle mapping. It's not even 2D - it's just a % change per voltage of throttle position. There is a "driver requested torque", but I'm not sure of the interaction between that and the AT computer.