You did not find those notions in our Constitution. Under our Constitution, each state decides how it shall choose electors and those electors vote for president and vice-president. The Founding Fathers did not believe that states should be required to choose electors by popular vote. What you have written is what you apparently believe the Founding Fathers should have written. Lots of people believe that we should get rid of the electors and let the president be chosen by popular vote. But, we haven't done that yet. The electors are still choosing the president and vice-president. I believe that they are obligated to vote only for candidates who are qualified to serve. So far as I know, every elector has agreed with that view of their responsibility.
We're just going to have to wait to see if the Supreme Court wants to become a screening committee for presidential candidates. I don't think it will, but again, we'll have to wait to see. ;-)
My point remains: the function of electors is to cast votes for President and Vice President of the US. They have no other authority.