Rooney is offside, his hip and foot and those you can score with.
Valencia on his assist.
Yes the Crystal Palace game was indeeed away, and Zlatan is onside. It is Pogba who is offside.
All of them are offside goals. I can't find 7 at OT, but those 6 goals (4 at OT) are offside.
To be in the bottom half they'd need to be below Burnley at 26 pts, and with 20 goals better gd you'd assume they'd have to have at most 25 pts, meaning they need to have missed out on 15 points in these games to be in the bottom half, which is impossible since they didn't even take 15 points from 4 games in the PL (no other team would've moved positions above Burnley had United scored less). So the only way for this to have worked is if they had lost a bunch of other points in other PL games from offside goals but I haven't found any.