Ray, again thank you.
You are in the engine room doing the hard work, identifying aspects which could form the dots of information; its up to others how they put the dots together to clarify the overall picture.
Even with more focus on the pilot's action, any view would only be speculative; yet there are several recently identified technical issues which would benefit from a NTSB review.
We might never know why the pilots reacted as they did, but the operational environment could be improved; inadvertent GA switching, annunciation, AP overpower characteristic - why no disengagement / trim protection and annunciation, representativeness of simulators.
Re simulator training for illusions; the types of illusion being considered involve acceleration - linear or angular. AFAIR there are no training simulators capable of generating sustained acceleration.