I would assume that her maiden name is indeed Clark as the Superboy TV Series is a similar universe to the Donnerverse Superman films, where Jonathan referred to her as Martha Clark Kent. Since both entities were created by the Salkinds, I would definitely go with that.
Honestly, I don't know. I know that the "impostor" was killed by the "real" Lobo. I haven't actually read JL vs. SS, or the new JLA books. Maybe somebody else here has a better handle on the Lobo situation.