I agree, not only are you asking for a real collapse from Everton, but you're also relying on Luton picking up points. Even if you went with the lowest of points expectations for Everton it's a minimum of 4... Luton would need 7 to stay up considering GD.
Hard to see Luton picking up 7, particularly as the pressure mounts. That collapse away at Bournemouth undid any real prospect of them staying up.