J.Law would be great personality-wise for Stevie and she's a fantastic actress. But she looks absolutely nothing like her (what is this "resemblance" these people are speaking of?) and she's like 7 inches too tall. However, I really don't know how much that stuff actually matters to casting directors/the band (potentially). Reese obviously looks nothing like Stevie either and Stevie wanted her, so...
Bradley, on the other hand, was looking VERY Lindsey-esque in parts of American Hustle (probably just due to the dark hair/beard/blue eyes/70s garb, but still). He's also a fantastic actor.
Mick is the one who I can't really think of anyone that would be suitable.