This debate a bout how to feather an engine after a major mechanical fault on takeoff is entertaining but misses a key point in feathering propeller design.
All current single action feathering propellers (light a/c) use an "oil pressure to fine pitch" design.
Loss of oil pressure (IE: the major mechanical failure) above minimum feathering RPM will result in the propeller Automatically feathering as oil pressure drops off (the reason low pitch latches are required).
The only conditions that will result in the propeller completely locking are a loss of oil pressure AFTER the engine has decreased below min feathering speed AND the prop has reached fine pitch (An instantaneous ceasing of rotation with the prop already at fine pitch - very rare for an inflight condition).
Or a mechanical failure of the propeller or governor resulting in the inability to drain oil from the prop (in which case no pilot action will make it feather)
So: Do the feather drill carefully and make sure you identify the correct engine. If you have had a mechanical fault chances are the engine will feather itself before you touch the lever anyway.