I would argue that for the most part, Anya was never really a member of the Scoobies (I don't think Buffy considers her a friend), and also, until late S5 - S6, didn't really want to be.

Spike, unless we consider the time when Buffy was dead (and we really don't know enough about that period), never wanted to be a Scoobie. He loved Buffy, was very fond of Dawn and Joyce, but for the rest of the people, at very least, he didn't care about.