I guess my dual engine failure is not correct, or totally correct. Could still have been a partial power situation in the left if it was running on fumes and there was a fuel problem. I wonder if they can tell from the L prop how much power it was making.

Yeah for sure. If the left was at full power when this happened it sure makes the 404 look a beast in S/E situations. He may have let it get slow however, in which case the only thing left would be to reduce power on the good engine. It's either that or the fuel was running out due to ice clogging.