Your narrative is pretty close to what I had theorized, except for my belief that the 13th tribe was human before settling on Earth. However your explanation is sound and could very well be the explanation. I guess my only problem is that if the cylons had been created on Kobol, why is it explained that cylons (the centurions at least) were invented in the relatively recent history of the twelve colonies? If you watch earlier episodes, there is every bit of evidence to believe that cylons were invented on the twelve colonies, and not a technology that they brought with them from Kobol. In addition, I would think that the Prophecies of Pythia would have vaguely mentioned such a thing. Still, I think these are anomalies that can be explained based on your theory.
We can only wait and see.
No... I don't believe the Cylon Centurions are Kobol-technology based... For me there are two options... the Centurions got invented on earth, and through the final five, this technology could have travelled to the colonies...OR
The human-cylons on earth invented their centurions... the humans on the colonis invented through coincidence or gods divine influence the same type of mashine, just little diffrent in design and 2000 years later.... In this show I'd rather believe in divine influence.
And just to add to the overall discussion about aging Cylons.... there were absolutly no hints regarding the Cylons NOT aging. I have seen this show as a whole two times.... and up to Pegasus probably 4 times... (I kno I am crazy).... the aging of Cylons was never really a topic... the viewer asumed some stuff... but it was never really discusssed "on air"...
I believe all models of Cylon age... somehow... most of the seven models are simply not alive long enough to age... couse they get kicked by the fleet. And a person does not change that much in the timeframe of four years regarding age. Hairstyle changes... bodyfat might change... but not really the visible age of someone.