Thats basicalyl how i see it, with the caveat of Duran likely pulling away if he busts Napoles open. You can't fight Duran badly hampered with cuts using the kind of hands-low reflexive style that Napoles did and expect to win too many exchanges.
When I read your post I was thinking that DeJesus seemed like a very solid lightweight as far as size goes, so I checked on boxrec and learned that the first Duran/DeJesus fight was actually at junior welterweight, and DeJesus challenged for Cervantes' junior welterweight title just over a year after Duran/DeJesus II....so I don't know if going down to junior lightweight would even have been an option. I didn't know these facts, but I still think that DeJesus would be faced with some problems against naturally bigger fighters like Mosley and Oscar....he was definitely a very soild lightweight who would be a serious challenge for anyone at that weight though....in fact I think that he'd beat most of them.
I'd comfortably pick him to beat the likes of Camacho, Ramirez, Rosario, Mancini, Haugen, Roger Mayweather, Bramble, Pendleton, Johnston, Bazan, Castillo, Corrales, Casamayor. Not sure what to make of Floyd Mayweather. His talent is undeniable, but I wasn't impressed at all with his stay at 135 and I think DeJesus would beat the Mayweather we saw there. Had Floyd chosen to stay at 135 though, perhaps he could have distinguished himself form the pack more and I may have given him a better chance against DeJesus. Off the Floyd I saw, DeJesus by decision. Mosley and Arguello are close to 50-50 fights I think. The Mosley fight in particular is an interesting one. I think the key will be whether DeJesus hits hard enough to earn Mosley's respect and keep him from moving in and working the body where he can slow DeJesus down. If Dejesus can keep him off his chest I see his naturally slicker boxing skills winning the day. Arguello has a good pucher's chance here, but should be outboxed for the most part. Not beyond Alexis to find the thunderbolt that turns things though. Could go either way.