I will say Hatton is one of the best 140 pounders right now and he'd beat a lot of people just not these guys:

Miguel Cotto - he's young, he's strong, he's HUGE at 140

Floyd Mayweather Jr. - he's slick he's too fast, he's got power and very fast hands (Hatton's style would be good to go against PBF though so it wouldn't shock me if he wore Floyd down)

Other than that all you have are "close match ups" and some "if-y" style fights

Castillo would be tough for Ricky but not impossible

Diego is tough but he'd be beat

Ricardo Torres a good tough fighter

Junior Witter a quick fighter good boxer

But honestly I would favor Ricky vs all those dudes