Yes, but that relates to agent fees, rather than in-contract payments.
I (as a tax professional) very very much doubt that any PL club is paying players in a 'dodgy' way to avoid income tax/NI (except for the agreed 20% carve-out for "image rights"). Just look at the trouble that Rangers'...
Absolutely not! I can't recall where I saw/heard/read it, but they amalgamate the stats from every single reported-upon football game around the world, so the player/team stats are constantly evolving and updated.