I think it is naive to believe there will be any sort of consistently applied rule. It will be based on the whims of whoever manages this initiative. They are

I think it is naive to believe there will be any sort of consistently applied rule. It will be based on the whims of whoever manages this initiative. They are only using fact checkers because it gives them someone to point to and say "Look we didn't make this call, they did". This is like a money laundering scheme but with brand reputation risk instead of money. Facebook will retain absolute control and the people running this initiative will do whatever the brass tells them to, this program is just for deflecting complaints.