Carlos Ortiz, Ike Williams, Julio Cesar Chavez sr, don't think Napoles would have a walk in the park with any of these guys.
Just to throw this in the mix, those who saw SRR at lightweight said there were none to compare with him.
Napoles was an absolute master boxer who fought mostly above his natural weight so he could get the bigger fights. He could more than hold his own against any lightweight in history. As far as skill goes there isn't many better than Napoles. He was known for his off nights but avenged most of his knock out defeats in style. I think if you give him a trilogy against all the great lightweights he at least wins one fight vs all of them, even Duran. I'm not sure about SRR though.
Would Jose not be a little Frail in a Tough Fast-Pasted 15 rounder ? Jr Welter might of been his Happy Medium ? I Think Pernell Whitaker or Henry Armstrong could make it rather interesting, Alexis Arguello with his long Straight Armoury might be able to Cause a Cuts Problem, (Albeit if Vilomar Fernandez could Frustrate Alexis Jose should be able to with his greater Firepower an Added Threat, Duran of Course ... And a Dark Horse Possible how about, Heavy Handed Rodolfo Gonzalez..?
Napoles was immensely talented, but I think that welterweight suited him better than lightweight did. I would make Duran a clear favourite, and I think that Whitaker, Leonard, and Canzoneri could all beat him as well.
I think the best of Jose Napoles was past when he became welterweight champ...kinda scary isn't it? Regarding vs Duran,...Mantequilla was Esteban DeJesus squared IMO.
There's no one who is going to be more than a slight favorite. I would suggest the usual to give him trouble…. Duran, Leonard, Chavez, Whitaker, Gans, McFarland… maybe Beau Jack once in a great while would cause trouble.
No one should be seen as a heavy favourite against him, but he shouldn't be considered a heavy favourite over any of the very best either.