Yes, the appointed VP has to be approved by simple majorities in both Houses. Republicans would have to be stupid (redundant, I know) to approve anyone before 2022.
Don’t know that Newsom’s being from California would make him ineligible. That only kicks in when counting Electoral Votes.
Appointing Newsom would be counterproductive. I don’t think he could garner any Republican votes. Both previous VP appointments, Ford and Rockefeller, were not seen as threats by the democrats who controlled both houses at the time.
Some Democrats, tried to block Gerald Ford’s appointment as Vice President so that in the absence of a Vice President, Carl Albert, the Speaker of the House, would have been first in line for the Presidential succession. Then when Nixon left office, Carl Albert would have become President automatically.