Of the aforementioned Operators, the Purifier is the only one whose class' branch differs with the original. She is also the only one who is available from headhunting instead of being a welfare Operator.
It is worth noting that all three of them are formerly 3★ Operators affiliated with Op Reserve A1.
Unlike the original Hibiscus, Hibiscus the Purifier is affiliated directly with Rhodes Island, likely because she is now a matured, full-fledged independent R.I. instead of a rookie reservist Operator.