There also seems to be some gray area as to whether a former twice-elected President could be elected or appointed VP, and then assume the office and finish the term of a dead or resigned President.
I know Snopes has lost a lot of luster off its reputation lately, but there’s a good summation here:
https://www.snopes.com/fact-check/former-president-becomes-vice-president/
“There also seems to be some gray area as to whether a former twice-elected President could be elected or appointed VP, and then assume the office and finish the term of a dead or resigned President.”
I have pondered that myself.
I believe a governor, or mayor, in Louisiana(?) did that many years ago.
Perhaps one of the Longs?