Not true. We no longer vote for President and VP from one list. Remember the votes are for separate offices since the 12th amendment. So Zero’s votes do not go to Biden. Now does this mean that we could have President McCain and VP Biden?
Remember that political parties have no real standing in this under the Constitution.
No, Biden's votes go to Biden. If the ticket took 300 electoral votes then Biden would get 300 votes as vice-president.
Now does this mean that we could have President McCain and VP Biden?
No. In my scenario above, Obama would have 300 electoral votes and McCain would have 235. Obama's disqualification isn't going to change that. But say they disqualify all of Obama's electors, then McCain still has 235 electoral votes, not enough to win. If it goes to the House then they will pick a president. Since the majority of the state delegations are dominated by Democrats then I'd expect them to pick Biden as president.