I wish I had any. Unfortunately the waters have been muddied by fields like criminology, which are basically limited to a liberal analysis of the all-to-abstract individual, psychology, etc. Like of course things like crime, and justice are a reflection of class-struggle–so in analyzing things like gangs, especially in the period of history you referrence, this generally becomes subsumed into broader theoretical concerns.
To (try and) answer your questions what separates the BPP from something like the crips is, first of all, ideology (see Revolutionary Action Movement), which, through the struggle of some dedicated revolutionaries, precipitated into a line, and program, which responded to the conditions of its time.
What confounds us is how can something like the Crips–which as far as I know was started because some guy got mad at being beat up at the gym…–come to dominate a whole era after the demise of the BPP?
At this point I can only speculate: yes, from the broadest view point the gangs that came to define the 70s–90s were a counter-offensive against the Black nationalism of the 60s, and insofar as the Black national question is a (big) component of the proletarian class struggle in this country we could call it a counter-offensive of the ruling class. BUT, the question remains, was it a conscious effort by the state, or a secondary effect of the decline of the World Proletarian Revolution that was happening at the same time? Was it a strategy, or simply a tactic to nurture these violent, petty conflicts against these revolutionary organizations. Etc. the connection is there, but remains to be fully fleshed out.
Also I wrote this on my phone so typos galore!