I see no one from N90 has chimed in yet, but I can answer your first question with some degree of certainty . . . In a big TRACON like N90, C90, SCT, etc . . . a controller is assigned to an 'area' within the facility and certified in all of the sectors within that area to become a CPC. A Big TRACON might have 5 or 6 areas with 6 sectors each in them. SCT's areas are set up around the bigger airports, like BUR, LAX, LGB, SNA, and SAN.