Also, their positions, especially Kosha's, are interesting. She writes very little, says not to bother her, there's no analysis, nothing useful, and she appeared late (institute - not institute, usually appears much earlier). It gives the impression that she was already mentally prepared for her execution and doesn't really care, because she's a baron's DD.
In general, Del also seems to be playing a passive role, but she's not very active in life, so I'm less sure about her. Although, the possibility that they are all mafia cannot be ruled out.