Maybe we're on Earth MkI, which the Vogons destroyed and the BSG Earth is the Earth MkII that the mice rebuilt?
Seriously though, I have no idea where the puzzle pieces fit. My guess on "Watchtower" is that they were looking for something that could be discerned as obviously not coming from a Colonial origin. That way the viewing audience knew something really wacked out was happening. Really wacked out, like.. I dunno, maybe a handfull of beloved characters realizing that they *are* the enemy...
Wish they would have used the Hendrix version though.