Until fairly recently the single person outside the heriarchies of collecting organisations who knew most about BMI, ASCAP, SESAC, Harry Fox, etc (broadly, the America collecting societies) and where the bodies were buried was the legendary bass player Les Hurdle. I notice his bio which used to be easy to find seems to have disappeared from the net (unless you dig deeper than I). I thought he was still alive, although he is by now of a considerable age.

Will the AFofM not guide you in this? Local 47 used to be one of the most activist.