George Harvey, The Lovely Bones (2009)
Buffalo Bill, The Silence of the Lambs (1991)
Demon, Insidious (2010)
The Death, Final Destination (2000)
Hannibal Lecter, The Silence of the Lambs (1991)
great choices! for that specific movie genre, you hit the mark.
those two come to mind
kevin spacey in seven
and brian dennehy has john wayne gacy
but for creepiest, I think you hit the mark
George Harvey is really a despicable person, I can't stand him.
The others are plain creepy, I mean, what else can you expect from a demon or a cannibal?
Buffalo Bill looks like a typical lunatic, whilst Death (aka Grim Reaper) is just doing his job a bit overzealously.