Regarding over RTOW: Its not a PA-32, its a jet. 2 tonnes over is 1.5% more mass and not significant on two engines. At all.
Re air law. Historically regulators accept country of origin certification. I can’t recall a type for which approval was withheld by a regulator apart from some ex Soviet types. I think if approval were to be specifically withheld then overflights would be disallowed. I guess we just might see what happens if the Trump/China foolishness gets anymore out of hand.