I'm convinced that this will be the Sunday game, I'm not one for conspiracy/victim theories but I feel that UTD if the get through in the EL will have to play on the Sunday, Arsenal would prefer to play on the Sat as they will have the return leg for the Barca game the following Wednesday and Chelsea would prefer the extra days recovery from the PSG game. The conspiracy theorist would say that the FA's premiere tournament would see the FA wanting the 'Bigger' sides in the SF so I think they'll bend over backwards to get UTD, Arsenal and Chelsea having 3 of the 4 spots.
Long story short I'll bet my bottom dollar UTD V West Ham and Everton V Chelsea will be the Sunday games.
The only thing that could go in our favour is if the Police stay they don't want upto 15'000 Chelsea and West Ham fans travelling north on the same motorways and trains on the same day.