Im new to Logic and mixing in general... is it possible to import an MP3 and then separate the individual tracks (drums, bass, lead guitar, etc.) from the original and then save the new song w/o the respective part?

I think the short answer to this question is "no." Sorry. Unless there's some very high-tech device/plugin I don't know about. Melodyne can do polyphony, but even there, it uses frequency and not timbre to separate the sounds. There are folks far more knowledgable than I, however, that may know something I don't. I'd wait for final word from one of the "biggies."