I think these may legitimately be unused.

An early version of Phame allowed a post to appear on multiple blogs, but we scrapped that to make the UI simpler since there wasn't a very strong use case for it (and we could always do some "crosspost this..." sort of thing if we wanted later).

Phame blogs also originally had blogger membership lists, but that was obsoleted by policies.

So we can probably just remove them wholesale? Sorry you did all that legwork!