Robert Tucker's _Stalin in Power: The Revolution from Above_ disagrees as far as the Ukrainian famine is concerned. As Tucker tells the story of the 1930s, Stalin's assault on the party was the result of the fact that the Ukrainian famine had undermined his position. And certainly that part of the Great Purge that hit the army left Stalin's seat very shaky indeed, as he found out between June and December of 1941.
But haven't you forgotten which side you are arguing for? You started out saying that those who saw "DK [as] a literal example of George Orwell's anti-communist fable ... have relied on poor evidence and in many instances resorted to outright falsification..." Now you are saying that the lies and violence committed by the pigs in _Animal Farm_ had "exactly the function [as] the lies and violence had in 'Democratic Kampuchea'."
Not that I mind your making the case that _Animal Farm_ can shed some light on what happened in "Democratic Kampuchea," after all. But are you sure that this is a point you want to make?