I would expect those electorates could not vote, and instead, the electorate of the actual remaining majority (Libertarian) would be sent to the EC conference.
Democrats are only going because their candidate was assumed to be legitimately elected by their people. They don’t go if he wasn’t.
Dream on, it would be thrown into the House of Representatives, where anything could happen.
Electors are free agents. They can vote for whoever they wish when the electoral college meets in the state capitals in December. They do not have to vote for official candidates. The House of Rep., however, could consider only official electoral-vote getters from the top three, if it were to choose a president.