We know the engine was operational at the time of impact. This is because the prop was not in a freathered position.
You cannot draw that conclusion from that evidence.
... two possibly positions of grd idle of 52% or flight idle of 72% ng.
King Air operators have a variety of policies in regard of where the condition levers are set. For the 4 bladers, I believe the low idle setting is 60%, not 52%. The lever can be set at intermediate positions (e.g. 62%). If they needed airconditioning that morning, it is possible the R engine was at 62%, with the left at 60%. It is possible both were at 60% - or 62%. It is unlikely that both were at 70%.
With out oil px the prop will not and cannot stay in fine pitch.
In this case the posibity of auto freather may or may not have worked.
Contradicting yourself. You seem to be saying that with the loss of oil pressure, the prop will feather. Then you say that, without oil pressure, the autofeather may not work. (!)
There is plenty of oil pressure at all normal engine speeds. I believe there is plenty even at speeds as low as 20% Ng. During start, the prop begins to unfeather well before the Ng is fully up to speed.
Auto freather only purpose is to help the pilot from removing power from the wrong engine if there is a problem.
Wrong. The pilot can still inadvertently feather the good engine. If the bad engine has autofeathered, the good can still be manually feathered.