Something that is apparent to me, is that once the aircraft was in the fully developed stall, the right roll was effectively a side-slip/bank as the direction of flight changed and became stabilized once the wings were leveled.
No mention has been made of any rudder inputs, and it looks as if there was no spin element in the descent. The final roll to the right may have been in the process of being corrected at the time of impact, and hence the left wing low and the tail yawing to port. The same could have happened if someone planted their foot on the right pedal shortly before impact, i.e causing the yaw and left wing low.
What was causing the roll to starboard? Some symmetry problem, or payload/fuel out of balance and no flyable airspeed to compensate?