I don't think the issues with Cass have much to with economics, actually. Her situation is so special it hardly ever reads like anything that could have a comparison in the real world. Money is a non-issue for her, and I never got the feeling that the way she was written had anything to do with that.
I'd say the issues with her characterization are more on the side of genetical determinism than social determinism. She's the daughter of Cain and Shiva, so she's exceptionally good at what she does, and she turns bad. Most of the other members of the Batfamily fit into that pattern as well, the social background one and the genetical one aren't necessarily mutually exclusive.
It always seemed to me (especially when she interacted with others her age) that she was like the stereotype of the quiet Chinese exchange student.
Not sure. She seemed to get on okay with the members of Young Justice when she met them, and of course there's always Steph. Until Bruce decided Cass should stay be Batgirl and shun boys, I don't think she ever had much problems in that direction, as opposed to a lack of inclination for non Bat-related life.