Now last gen games that got a re-release are going to be re-re-mastered for new PS4 Pro patches and in worst case scenario re-re-releases. I wonder if Sony is putting some restrictions if developers can release the same game as a remaster for PS4 Pro or if it will only allow for patching. It would be very interesting to see GTA V re-re-released for PS4 PRO and seeing some earlier gen games getting remasters too. 

I doubt they'd let them resell them. They'd definitely let them add a free pro patch though. GTA V would be a good addition.

Hm... No. As they said, the patch will be free and available online. The only difference is that new covers will have the "PS4 Enhanced" sign. It is not like remasters from old generations, it's the same games with upgrades for HDR/4K/framerate/resolution and graphical effects, according to each devs desires.

I don't think they allow releasing the same games again as Pro versions. It's either a patch or no Pro support for existing titles. This, of course, is not knowledge, but I imagine they don't want that happening.