Interesting matchup. There's no doubt that Starling has the counter-punching abilities and defence to give Duran stylistic problems, and he's the bigger man, too. But Starling was a bit of a frustrating fighter who looked fantastic in spells, but just never seemed to quite put it together for a full fight - the Honeyghan masterclass is the big exception, off the top of my head. But Honeyghan by that stage had abandoned any attempts at boxing and was tailor-made for Starling. Duran wasn't a concussive hitter at Welter and Starling, the dodgy Molinares drama aside, could take a shot. I'd probably take Duran to win a hard-fought decision, with Starling a little battered but still unbowed by the end.
The Montreal/Palomino version of Duran beats Starling. Just a class above as fighter. Starling probably takes a beating late.
Marlon has a shot to beat Roberto, but that physicality on some level would bother him late. Duran by SD
Starling and Honeyghan really didn't like each other, which may also explain Mooch's unusually focused performance. As you say, elsewhere he could be frustrating, choosing to mug and spoil and basically letting fights slip away. Starling is smart and tough enough to frustrate Duran and make it to the final bell. Assuming this is the Montreal or Palomino Duran, I think Duran wins a decision. Any lesser version could get picked off.
As skilled, talented, and highly underrated as Starling was he was too hot & cold of a fighter to beat someone like Duran. Especially the Duran who beat SRL. Starling could be a mesmerizing fighter at times when he brings the heat and he can stylistically give Duran problems with his defense and counterpunching but he always had a bad habit of stalling or clowning too much. Duran would not give Starling anytime to breath. Duran wins by one sided decision.
Regardless of whether its "honeyghan starling" or "ozaki starling" i dont think stylistically theres anything moochie can do to avoid a sustained slow beating for 15 rounds .He"s not fast of foot or a mover and this duran would just cut him off anyway. Durans defensive skills and face that never got marked would walk through any occasional counter...
You can't say "Starling was too up and down to beat the version of Duran that beat Leonard". I could just as easily say Duran was too up and down post Lightweight to beat the Starling that pasted Honeyghan. Both at their best I'd take Duran, but we're looking at two inconsistent fighters. It's unfair to hold it against one and only take the other at his best.