I took another look at the pictures....and yes, both engine propellers appear to be feathered. Very interesting.
It's highly unlikely the props feathered without being commanded. Prop levers are full-forward. It's possible G-force or blunt force from impact pushed the levers back forward. So difficult to say. But examination of the cable positions will determine that.
A more likely scenario is that the props feathered as the engines separated from the aircraft, as the cable on the prop governor pulled away from the airframe.
This would be consistent with prop lever position and the inflight break-up.