Fellaini as a striker
Fellaini as a midfielder
Young as a striker
Mata as a winger
Rashford on the right (only 1 match I think)
Lingard in the middle
Young as striker, Mata as right winger, Di Maria as striker, Rooney as central midfielder.
The only conversion it has worked is Blind as CB.
Fellaini played as a striker/support striker at Everton and was very good there.
Young, I guess was an experiment because he done well in the U21's a few days prior to him playing him there, but I doubt it will happen again.
Mata's best form, in my opinion, come playing on the right last season. Also started off as a winger at Valencia.
Rashford played in the wide areas a lot in the U18's, so I'm told.
Lingard in the middle has been good, in my opinion. Prtetty sure he played there for the under 21's too.
Again, like Young, I think he only played Di Maria up top once, if I remember correctly, and that was in a 352, where he was able to drift out to the wing - similar to how he used Robben in the world cup. Didn't work, but it was worth a try.
Rooney was played in midfield long before Van Gaal. I could agrue that Rooney's best performance (Newcastle last season) in centre midfield.
I honestly don't think any of these ideas were outlandish.