In regards to "the good Lion by whose blood all Narnia was saved" (LB), through Aslan's sacrifice, he did two things. [...] Two, because he sacrificed himself in such a way, Edmund didn't have to die and thus was able to sit with his siblings on the four thrones, and (sort of a 2b), the way Aslan returned in the final battle saved Narnia. True, he probably could have done that last part either way, but this happened to be what he chose.

I agree. Aslan saved Narnia by defeating the White Witch, through those two (or two and a half) things he did.

I think that the main point, what really "saved all of Narnia", was not his death, but His Resurrection. That is where the true parallel lies. Anyone can die for his friends--only One can come back to life after doing so.

Very good point. The Resurrection is the real victory. His death wouldn't be much use - here or in Narnia - if it had not been followed by his Resurrection. Paul in Corinthians 15 says so, too.