Not likely. They fought before, and it was extremely one-sided. JMM only landed a ridiculously low 15% of his punches. 
Styles make fights. JMM has always done well against Pacquiao, because Pac has trouble with counter-punchers, and JMM is one of the best. But Mayweather is an even better counter-puncher, and bigger, stronger and faster than JMM. JMM needs an aggressive fighter to come to him in order to counter-punch. Mayweather doesn’t offer that opportunity. When JMM, who is not comfortable with being the aggressor, tries to go after someone like Floyd, he’s like a fish out of water, and Floyd can take advantage of that, easily. Granted, JMM has bulked up since he fought Mayweather a few years ago (very little doubt in my mind he’s on PEDs), and Mayweather has probably lost a little of his speed. A rematch would probably not be so lopsided, but I don’t see the outcome being a lot different. And the fight would not be nearly as exciting as the ones with Pacquiao, there would be very little toe-to-toe action.
Retirement for Manny would not be a bad idea. No fight that he likely can make is going to change his legacy at this point. It’s not inconceivable that he and Mayweather could yet meet, but the fight won’t generate nearly the interest it would have 2-3 years ago, and the outcome won’t much affect how these fighters are remembered. They and their handlers will, and should, be remembered as world-class idiots who blew one of the most awaited and definitely the most lucrative match of all time. The legacy of each should be downgraded a notch or two because they avoided the one fight that would have measured their worth more than any other. Arum in particular should go down in history as one of the greediest, most destructive promoters of all time.  I can’t think of anyone who has done more to destroy the sport than he has.
But big money is hard to resist, and I think Manny will almost certainly have a few more fights. I would like to see him fight Brandon Rios, who he probably would have fought if he had won this fight, or maybe Robert Guerrero, who may be the best welter in the world now. Guerrero has been calling out Mayweather and Pacquiao for a long time, and after a very convincing win over Andre Berto, he may finally get his chance. He would probably jump at the chance of fighting Pacquiao even now, as it would represent a huge jump in money and exposure for him. But after a vicious KO like that, Pacquiao would probably want to rebound with a lesser opponent, to get his ring confidence back. 
Hard to say where Marquez goes from here. At 39, he should be retiring, but he’s now making far more money than he ever did before, so like Pacquiao, he will probably hang on as long as he can continue to make big fights. I guess now he has his pick of anyone in the 140-147 divisions that he wants. I’m not convinced he can win any of those fights, though. As I said before, though he has a style that makes him very good against Pacquiao, that doesn’t necessarily translate well to other fighters, even ones Pacquiao would be expected to beat easily. Noteworthy that even as he was clamoring for the third fight with Pacquiao a few years ago, he was avoiding meeting other fighters that Pacquiao would have been expected to outclass, like Amir Khan.