I remember having conversations with my brother about Hashcash at the time. There were plenty of nerds that followed that mailing list that had similar technical and political ideas, so I think you'd find a high number of coincidences within an audience that I'd guess was a small multiple of the number of people active on the cypherpunks list. There definitely were a lot of people at my brother's college discussing the same ideas.

FWIW my brother did his own bit of Satoshi hunting with coworkers at his hedge fund. They didn't come to a strong answer but my brother believed Nick Szabo was probably part of a group that helped edit the paper. He suspected Hal Finney was involved similarly at a minimum.