OF vs CF replacement level in fantasy is almost a wash. It's not like real baseball.
Stanton is 3 years younger and projects to give you about 10-20 additional points of wOBA. If it's a garbage 5 category league with SBs being skewed heavily then there's a case for McCutchen but that's really the only way a rational argument can be made.
Trout > Stanton > Harper > McCutchen
And yah, Miggy is definitely in there somewhere too.