I don't know how clued up Spotrac are on this stuff, they are mostly a US site - very good for the stuff like the NFL where all this stuff is public knowledge, but I doubt they have a great amount of insight here.
That said, a lot of this is probably right. I'm still surprised by the reporting that Martial is on £250k p/w, I can't really think of a point where he was ever good enough to get that type of payrise.
I think Shaw is likely on more now with the new contract.
Some of this I'm sure is incentive based, Brandon Williams for example I'm pretty sure a bulk of this is related to playing and that's NOT his basic salary.
Sabitzer's I'm assuming is a % of his wages being paid for by the club, if not and they're covering 100% and that's ACTUALLY what he's on, that's crazy and just shows the difference between the PL and other leagues.
Also where the feck did they get these numbers for Maguire and Heaton?