I'm not familiar with Mazzinghi. I like Norris, Wright and McCallum. Hearns had some good wins but didn't have many fights at 154
Mike McCallum achieved the most at 154 of any fighter in history IMO. He won the WBA title in October 1984, defended it 3 times before stopping Julian Jackson in 2 rounds, racked up another couple of defences, before beating further quality opposition in Milton McCrory and Donald Curry. He never lost a fight at 154. Winky Wright did manage to win the undisputed title, but considering he spent the vast majority of his career there (unlike McCallum), I don't think his star shone any brighter at 154. Wright lost 3 times at the weight (Harry Simon, Julio Cesar Vasquez, Fernando Vargas), and although he beat Shane Mosley twice (a lightweight fighting at light-middle), the rest of his resume is merely decent, there are no wins over bona fide lightmiddles to match McCallum's wins over Jackson, McCrory and Curry. I suppose if you are talking about achievement solely in terms of number of alphabet titles won, then Wright it is. But IMO building a good resume, fighting top opposition and avoiding defeat in doing so is a great achievement. Therefore, I say it's McCallum.
I don't think anybody has any great knowledge of him. He's not particularly well known. He seems to be tough little fighter, who hit pretty hard. 2 time linear world champion and he never seems to get a mention which is why I would include him. I would have all the other above him though in honesty.
Pretty close but id reverse hearns and norris. I dont think hearns had enough fights at 154 to be above norris.