I really don't think it matters too much, but as a mental exercise I present the following.
@Whiteboy, I'm going to start with your second point:
Sin is passed down from generation to generation...because of Adam. Yet it doesn't seem just that others on a far planet (part of creation) would suffer because of our sins while they remain innocent.
Would they remain innocent? Adam and Eve sinning introduced imperfection into the "natural world". From that point on, nothing merely "natural" could ever be perfect again. I see no reason that intelligent life hundreds of light-years away would not be similarly effected by that. It might seem unfair, I suppose, but I think it would just magnify how great a crime was the sin of Adam and Eve. Perhaps it wasn't simply their eyes that were opened to Good and Evil, but the whole of the universe.
From that, your point #1 would follow: death is introduced to the whole universe, not simply the Earth.
3 The Father sent the Son to die for the sins of the world. If they are not innocent, I have a hard time believing that He would have to go to every other inhabited planet to die multiple times for each planet's sins. I believe His sacrifice was unique and complete.
Why would the Son have to go to every other inhabited planet? Would not His perfect sacrifice be sufficient for all? Besides scale, what difference is the distance between Judea and Japan and the Earth and Seti Alpha 5?
Imagine if John 20:29 was not only referencing us, ("Then Jesus told him, "Because you have seen me, you have believed; blessed are those who have not seen and yet have believed.") but also referring to those from Dantooine who listen to the prophets sent to them about the sacrifice halfway across the known universe?
4. All of the Bible is focused on the Earth. For examples, He created Earth first...then the rest of the universe; and Jesus became a human to die for the sins of the world.
Well, yes, the Bible was written to the people of the Earth. Perhaps we are only the firstfruits (James 1:18)of His creation, not the sum total of it?
If we accept something like Fermi's Paradox (if there were intelligent life out there we should have found it or be found by it already) to mean that we will never contact intelligent alien life, then it would be strange to have the Bible reference them.