I like parts of the logline. I'm a little disappointed it's not a member of the band that's on the comeback trail. 'Band Manager' has less of an appeal than musician. Hard to feel empathy for his journey to if he already runs a nightclub. If Steve craves fame, running a band is not the best answer to his desire, he needs to be out front in the band. I agree with others when they say we need a reason it is not going to work. And 'moderately' successful is not the best set up for maximum conflict. Maybe they left the scene under a cloud and he wants to put things straight.
A heard about film recently made about a man who declared on his death bed that his old band unite. This is a great concept. I'm not sure yours has that level to peak interest.