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.
Good point. And RDM was asked about all those things, and confirmed we'd get answers for all of them. I mean, we have 9 episodes left. They better spend them answering questions and resolving things!