I find all of these theories rather compelling, but I feel one fundamental element is being left out. There's still the question of the mystical nature of a lot of these events, the mystical quality that has been present from the beginning when Head-Six began talking about God's plan for Baltar. There appears to be something
orchestrating these events. There is something behind Head-Six, behind the visions, behind Starbuck's death and resurrection. All of these things are no doubt tied into the 5 and Earth, but there's simply no way to truly say what is going on. I think all these timelines are compelling and they may have a lot of truth to them, but I feel that there is something much more complex behind the rebirth of the 5 and possibly behind everything in this repeating mythological cycle. I don't think any possible synopsis can be complete until we can answer these questions, too.