The Founding Fathers only said in the U.S. Constitution about presidential elections (only after debating among 60 ballots for choosing a method): “Each State shall appoint, in such Manner as the Legislature thereof may direct, a Number of Electors . . .” The U.S. Supreme Court has repeatedly characterized the authority of the state legislatures over the manner of awarding their electoral votes as “plenary” and “exclusive.”
Only the state possess the “Appointment” authority, in whatever manner it sees fit. For example, it could pass a law saying, the Governor shall name the Electors. Or, the legislature shall name Electors. Or, the political party shall name Electors. However, this “plenary” authority does not extend to permitting citizens of one state, through whatever means they name their Electors, to compel these Electors to act as de facto Electors of another state. Apples and oranges. (Watch the debate between Professor Lowenstein and Dr. Koza at the Commonwealth Club, posted on my blog.)