Which of these fighter would've done best against Mayweather had the fights happened-

In order, with the weights and year listed in original post:

Mosley
Pacquiao
Williams
Margarito
Cotto
Casamayor
Johnston
Freitas
Vivian

 

Paul Williams. There are a few on that list that could beat Floyd but I see Williams making easy work of him to be honest. Quintana was able to outbox him and beat him to the punch that night, but that doesn't mean Floyd would. Carlos fought the perfect fight that night. Also, Quintana wasn't heavy handed by any means but he still had ten times the punching power Floyd has, could floyd keep Williams off?. I don't see how.

Floyd would have had his moments in the fight but Williams volume and power would be too much. There is a reason Floyd never uttered Paul Williams name.

 

Who wouldn't say that the last four rounds against Margarito would have been the most interesting of Jr's career. A big strong Mexican look for the finish.

 

shane and pac

shane power and speed which caused may a couple of problems in thier fight a fresher fighter might have landed that big right hand a few more times

and pac in out movement, speed and huge left hand shots

williams was just a busy fighter didnt use his height - mayweather would counter him silly i feel bad talking about a guy who cant walk and was world class

margarito would have been outpointed all the way wouldnt win a round

 

Old Mosley almost ko Floyd in 2 rounds.
Prime Mosley would defeat Floyd widely.

 

Floyd avoided them all. He is a cherry picker.

 

Mosley was very weight drained at 135 by the time the year 1999 rolled around, so I don't get why he has so many votes, now if we talking 147 pound Mosley in the years 2000-01 then I would understand why the votes swayed towards him.

 

Theres not a fighter to walk the planet ever who could only be beat by KO. Thats a highly novice statement. Everyone has weaknesses and styles that trouble them. And if its anyone now who could only be beat by KO, its rigo, not floyd.

 

Youre just a boxing fan, not a boxing obesrver. Pac absolutely troubles Floyd, and Floyd runs through Cotto anytime in his career. It would probably be easier for Floyd before, when he still had 100% of his legs.

 

I picked Mosley, since only one can be picked. Shane Mosley at 135 was a damn good fighter. He would have been a problem for Floyd or anyone else. If I had an option to choose a second fighter, it would have been Manny Pacquiao. I always felt Floyd would beat Manny, but the Pacquiao of 2009 was prime and had the power and angles to hurt Floyd possibly stop him. I still would have picked Floyd by decision, but if Manny hurt Floyd the way Mosley did, he had the power and angles to finish the job.

 

Shane Mosley in 1999 would give him his hardest fight after that Williams. Everyone else he beats going away.

 

Paul Williams had the best chance . 6ft2 tall , 82 inch reach , throws a 100 punches a round , greater stamina than floyd . Williams would have beaten Floyd with ease . Punisher by possible shutout or TKO . Floyd would have been overwhelmed like we never seen before .

 

It wouldn't have been easy, PBF is arguably the smartest fighter in the game and isn't an easy fight for anyone.:deal Williams never makes it easy for himself and for the most part fought dumb. So I disagree with your assessment. Although like I said in a previous post Williams along with Mosley give him his hardest fights of the list.

 

Vernon Forrest...the one who demolished Shane.

 

I can see the argument that Williams might trouble Floyd. Tall as hell, fast hands, good power, good chin and very busy. But the guy never fought tall. Always giving up his height advantage. And he had no defense. Slow ass Quintana countered him to death with ease. So did Lara. I don't see a guy that reckless beating Floyd. I would give prime Marg a much better chance because he's better at walking guys down and cutting off the ring and a great body puncher. Also had a granite chin so he would've ate Floyd's punches up.