Gold,
In Greeley’s case, the electors voted for a dead man. Such voted aren’t valid.
In your case, the candidate was alive at the time that the votes were cast. Thus, the votes are validly cast and should be counted by Congress.
Regarding the Baca SCOTUS case, there has to be some statutory clause that allows the winning or losing candidate to release a pledged Elector to vote for someone else.
Ex., in a 269-269 tie, someone will want to vote to determine the 3rd person eligible in the House. (2016: Colin Powell’s 3 votes put him into the hypothetical House contingent vote.)
The house that refused to count the EVs cast for Greeley did not do so because Greeley was “unqualified” when the Electoral College met (although he already was dead, as you noted), but because he was “unqualified” (because he was dead) at the time that Congress counted the EVs. That’s the precedent that needs to be overturned.
But if Congress pulled a Roberts and interpreted the precedent in the way that you set forth—that votes cast for someone who was dead when the Electoral College met should not be counted because the person was unqualified at the time of the vote—it still would be a dangerous precedent that should be overturned. What if a candidate is killed on the day that the Electoral College meets, and Congess determines that he died before the electors voted in certain states (perhaps those in the West)? Wouldn’t the proper solution be to count all of the EVs cast for the dead guy, instead of counting some of the EVs for him but invalidating others?