@ Zerograv :
It has been established that both engine propellers went into feather. We will have to wait to learn if that was caused by system malfunction, or if it was crew error when intending to reach for the Power Levers, or even for the Flap Lever, they instead reached for the Condition Levers.
Not familiar with the ATR quadrant, but looking at a photo, do you mean that : 1) retarding the conditions levers to Fuel shut off would automatically feather the props and 2) there is no push or pull button or notch to pass to get to the fuel shut off position ?