Lost series theories

I did end up getting to watch Lost last night.  We just went to my grandma's house and watched it on her TV since she wasn't there.  They said in the recap that season 5 was going to be all about answering questions and stuff, but honestly, I think I'm even more confused then I was going into the show.  I have all these random theories and they all have massive loopholes, but don't all Lost scenarios have a ton of loopholes anyway?

For instance... Locke has to get off the island to get the others to come back by dying (????) and I'm thinking, honestly, how is Locke dying going to get the Oceanic 6 to come back?  Then I'm thinking about Locke's past and how Richard kept popping up in it as the same age that he is now. So then I thought that Locke must go back in time to birth, knowing in his subconscious that he has to complete this mission of dying.  So then there would be two Lockes. One that would go to the island and of course get stuck there forever, and the other one that doesn't go to the island and would complete his mission by dying in LA or wherever he was when he died.  I don't know if that makes any sense to anyone else, and it certainly doesn't even make sense to me, but it's a theory that I have regardless.  

And how about that whole thing with Desmond having to go to Oxford to find Daniel's mother?  Since Daniel never got to finish the sentence, how will Des know what to do once he gets to Oxford, and how does him finding Daniel's mother factor into anything, unless Daniel's mother is also some kind of physicist that knows what's up on the island.

Does anyone else have any theories?