Much as we have hoped someone will flip things this season, that possibility was lost the day Cody walked out the door.
Paul is in the final 3, so mission accomplished there, and I'm sure he's confident he can win any mental comp against anyone, with only Josh a threat on physical, so he will decide who is sitting next to him at the end.
For this segment, he really can't lose. He just has to keep telling them that only veto matters, so the nominees don't mean a thing. That being said, I do think it's an opportunity for a gesture to Kevin, plus if he only noms one of Josh and Christmas, no matter what he tells them they will take it personally that it's them not the other. He'll tell them it's to hide their alliance from Kevin and make him feel too comfortable to try on the veto.
Then, if he or Josh or Christmas wins, it's no problem. If Kevin wins the veto, it's not really a problem either as then he's the bad guy who takes out Josh or Christmas, thus securing their vote for himself (Paul). He's likely sure that Kevin cannot win anything in H3, so he or the remainder of Josh or Christmas will get rid of Kevin then.
As I think about it, having Kevin in the F3 would probably be a good thing for Paul, because then he's got an easy exit without having to choose between Josh and Christmas - I'm sure he doesn't care, but they certainly will.
ETA - Of course I could be completely wrong about this

and surely enough, the folks at tvclubhouse seem quite certain that Paul wants Josh out now because he's the only threat for the final HOH comps. He's also the most volatile and made the mistake of asking if Paul and Christmas were a showmance (Paul apparently thinks he has a girlfriend waiting for him), so that's against him.
But Paul has figured out how to manipulate all of them - Josh's emotions, Christmas' crush on him, Kevin the man of his word - so none of it really matters I guess!