A couple of points (mostly read on this blog) stick in my mind, though not in any really coherent fashion unfortunately . .

The final 5 Cylon trigger at the nebular is also a signpost to Earth - some might say the final signpost. Thus, they have to be related. That is too strong a sign to be a random insertion by the writers (I'm operating on the assumption, mostly from what I've seen and some things RDM said in his interviews, that the mythology isn't completely planned, and thus not everything is going to make sense, but that they tend to have a general direction they are aiming for . . . )

The Cylons did seem to know that some humans would escape the attacks on the Colonies . . stationing a man in the ammo depot, for example, and putting Cylons on the Galactica.

Also, Galactica did seem prepared in some ways for the attack - it had a Cylon transponder installed in it, plus 4 of the final 5 Cylons seemed to have positioned themselves to be in Galactica.

But, the other Cylons really did seem to be trying to wipe these humans out of existence. If they weren't, then they have been faking it all along, and that would have required an extremely high degree of knowledge about what was to happen - eg, that Galactica wouldn't explode when being pounded by 4 basestars at New Caprica, etc.

So, it does look like two opposing forces, with limited knowledge of what would happen, trying to control events.

Roslin, Starbuck, and Baltar . . . who knows where they fit in.

Anyway, the more I read, the more I see some of these ideas have been thought of already, just kind of clarifying them for myself.

Cheers!