The photo in post No 267 would suggest that there was virtually no rotation of the port prop on impact, whereas previous photos of the stbd engine show blades sheared of indicating high power on impact.
As sevenstrokeroll has said the Garrett TPE 331 has a torque sensor which will cause the prop to move to a "torque feather" condition when the engine ceases to produce power, this is not a full feather, and the pilot must carry out feathering procedure to fully feather the prop.
I believe that the post impact condition of the props will prove a significant factor in determining the cause of this tragedy.