Your point is well taken, but that is dancing around on the head of the pin...but probably enough for a court to declare it a "political question" and not rule on it.
And there doesn’t need to be a certification of the national election. It IS just math. And legislatures can appoint electors HOWEVER THEY WANT. That’s the Constitution. Including the national vote numbers.
One again, there is no national popular vote - it would not just be "math" - there would have to be some sort of verification for the state to use it under a law allocating Electors to certify it. There is no official tabulation. I suppose they could say "as tabulated by the AP in their final count" or something but that would be rather awkward. It would also be 100% stupid.
Yes.
There doesn’t have to be an official national vote. Since they can pick EC voters based on ANY criteria they can just say that it’s the generally accepted winner of the popular vote. There doesn’t need to be any verification or official tabulation. They could literally just say whoever CNN says is the winner is the winner and our EC voters will vote for that person. They can pull a name out of a hat if they want. There are no limits and no need for official anything.