two possible causes come to mind, fuel mismanagement and flameout due to icing
Yeah, both of those seem like plausible reasons for a shutdown. And who knows when the engine shutdown and prop feathering was actually accomplished? There's also been a number of incidents where TPE-331 engines have been shut down by the pilot after getting an NTS indication accompanied by torque, RPM and EGT fluctuations following a rapid throttle retardation at high speed. Add to that the usual list of malfunction related reasons for an engine shutdown.
The control difficulty seems to have occurred sometime after the instruction to slow to 150 KIAS. Obviously the airplane would have been much less challenging to control at the previous higher speed and before the flaps and gear were extended. Now with the lower speed, higher drag and the need for more power on the remaining engine, LOTS more rudder will be required. That scenario can get out of hand in a hurry if one isn't practiced and/or doesn't anticipate it. Sawing back and forth with those roll spoilers only makes it worse.
It'll be interesting to see what the NTSB comes up with. Maybe in a year or two...
westhawk