The main characters in San Andreas are based on famous 90s Gangsta RappersSome of these are more obvious than others; Ryder is Eazy-E by any other name, given the obvious physical resemblence, and the parallel between Ryder and E in 'betraying' the hood and chasing money; Big Smoke is the Notorious B.I.G. Sweet is Dr.Dre, with a physical resemblence and intense loyalty to his 'roots' CJ is Tupac. There is a slight resemblence, it fits well with Tupac's mythos of being a warrior against the world, the fight against Big Smoke is similar to the rivalry with Biggie Smalls and later games give hints that CJ may or may not be dead, parodying the myths that Tupac is alive still.
The Green stuff from area 69 is ValkyrGreen viscous fluid? Military origin? Post-desert storm?
CJ's mom was a Black Panther or GTA equivalentmaybe even a high-ranking one who for one reason or another had to flee to South Central LS with a mistrust of the law, and a strong sense of revolutionary activism, she founded or possibly co-founded the Families note as a gang to self police the community. Under her leadership they may have gotten involved with things such as racketeering or theft as a form of taxation to fund their protection of the community, but not drugs as that would have severely negatively affected the community. Her kids (the ones we see) each have a different aspect of her outlook and philosophy Sweet shares her sense of community wanting to protect and serve the hood CJ holds her belief that one shouldn't be held back by their circumstances, as shown by his constant attempts to better his standing and Kendl understands her dislike of having to resort to criminal behavior to get by though the game begins with her death her influence remains throughout