One of the aspects of NuBSG's retconned backstory that never made much sense to me involved the Final Five making the Significant Seven. So they show up, bring some kind of spiritual salve to the Colonial-created Cylons, and then convince those Cylons to turn most of their race into slaves (the Centurions / non-humanoid AIs) and make themselves mostly a bunch of clones of only 7 different faces / personalities. It was all probably just a buncha crap made up on the spur of the moment to justify what how the Final Five fit into everything.
But it still would have been nice to see it play out first hand, and perhaps come up with a better way of presenting it and telling the story.
I always assumed that it was Cavil who basically changed things around so that the Centurions were made subservient. It gels well with his personality, motives and the scenes we see in "Six of One" and thereafter. While he may have wanted to be the "best machine he can be", this idea was an obvious contradiction of the Centurions motives, seeing as how they allowed the Five to construct humanoid versions in the first place.
It would seem the overall intention of the Centurions and the Five was to do a "do over" of the Earth humanoids and maybe somehow make a lasting peace with actual humans, to later include hybrids like Hera who would become "the future of both races" and "the shape of things to come" (which kinda sorta happened anyway).
This is in stark contrast to Cavil's view of things and, particularly if he had help from other vexed Centurions (the old school models), it's not outside the realm of possibility that he could've managed all of it on his own. He was strongly motivated, which "No Exit" makes clear.
Evidence from that episode seems to suggest that he was not only the first complete version of the new humanoids, but also someone who worked directly with the Five. This suggests that his role was more that of a liaison or partner than a mere prototype. So basically he was trusted by the Five and the Centurions and he betrayed that trust. This left him no choice but to block the memories of his siblings lest they turn on him before execution of the Plan.
As for the seven, it has been speculated before that it was not the intent of the Five that there only be seven, but rather that Cavil's betrayal went into effect before they could finish their work, perhaps create more models and make it so that they could procreate biologically. Having boxed them, Cavil alone lacks the knowledge and, rather importantly, the motive to finish the job.
It seems to be that, from a broader perspective, Cylon history can basically be divided into "Before the Five" and "After the Five", because their existence seems to wildly diverge between them. It of course remains unclear what role, if any, the events of "Caprica" played in this. That and the origin/purpose of the Guardians will probably only be semi-resolved in comics and other semi-canon works (if ever).
A fair point about Cavil, who could have been the puppetmaster behind any number of schemes. Twisting the state of the Colonial-created Cylons into whatever state post-Five.
I believe it was stated that Cavil's physical form was based upon Ellen's father? Perhaps he was created first, symbolically, to act as the guiding father figure of the humaniform Cylons. So that it would be one of their own, rather than the Five acting as rulers of the remade Cylons.
I suppose it's also possible that the entire thing of making endless copies of 7 models (including Cavils) could have been purely Cavil's idea. Perhaps Cavil and then the "prototype 6" were created ONLY as prototypes. And the Five had intended to allow the humaniform Cylons to procreate naturally so that each would be unique - as seemed to be the case on the Five's Earth.
Then Cavil, bent on reaffirming their nature as machines and not human beings, devised a machine-like social organization where each of the 7 human forms was treated as a "model". Copied on mass scale. Encouraged to think like machines; see themselves as disposable, identical parts to all the other models of their type. A desperate hack by Cavil, to make them as machinelike as possible under the circumstances.
As for B&C, I almost wonder if our intrepid traitor lady was actually a cultist from the religion of the One, that religion perhaps becoming perverted further into a Cylon worshiping organization by Sister Clarice. Could be how the rebellion started; Clarice encouraged Cylon solidarity and even divine providence. Except it got out of hand. The Cylons didn't just assert their equality, they decided to wipe out humanity and replace it with a superior humanity 2.0. That includes wiping out the cult, with no little irony.
Hell, maybe that's what happened to Clarice in the end. Perhaps she and the human core of her order were the first betrayed by Cylons they were aiding and harboring, slaughtered, and from there the rebellion began.
(I'm sure plenty of people would like to see that as Clarice's ultimate fate.)