Mayweather isnt really tired on making these exhibition fights? Fighting with a Rapper? What in the world is happening? 
Yes, he categorically says that he will do exhibitions only, so I doubt that May-Pac could happen. He is targeting 50 because they have a fall out. They used to be best buddies,
https://www.cheatsheet.com/entertainment/the-origin-of-50-cent-and-floyd-mayweathers-beef.html/
So they have a history, that's why he want's a "winner take all match".
50 cent had some history of boxing in the past as an amateur when he's still a teenager. Seriously?
Not sure if this is true as well. Amateur or not Floyd will whoop that a**.