If we accept a black and white nommies= evil, as SP suggests, Humanity dies.
Kusari is overrun completely.
I don't think Bretonia would be able to do a whole lot. The infestation had reached all of the colonies, and while perhaps less than in Liberty and Rheinland, She would still be subject to manipulation. I always had the impression that Bretonia was the weakest of the four*; having the bad luck to take engine damage, to arrive late, and to settle in the mostly-ice barrier nebula; having only three inhabited planets, all three fed by one. Sure, they might have good technology, or a large military, I don't know if they do, but I think Fortress Bretonia wouldn't last very long.
How would the Order even warn them? If everyone in Minor dies during the fight, will the Order elsewhere even know? Unless they have faster-than-light communication, the fastest way to carry news is to have ships act as couriers, using a network of Jumpholes and Jumpgates. Even If an Order pilot did escape, where would he go? Would he be able to get through Alaska and to New York, through Nomads and Navy? Is the cloaking technology going to last long enough for that?
Once Nomads become public knowledge, of course there will be resistance. There will be heroic last stands, all of which are doomed to fail. People will try to hide, to build bases in the middle of nowhere, but they will eventually be found. Groups such as the GMG, Dragons, Zoners, Junkers, etc who base their living in space, could probably flee, rebuild, and flee for a long time, but only ekeing out a miserable and fearful existence as they do. Eventually, their last ship would be lost, and they would die.
Outcasts, if they were used by the Nomads, would be the last to go. If the Nomads didn't use them, they would be pretty much dead the moment they lost Malta. The Corsairs would lose most of their food supply, weakening them, and while fighting valiantly to defend Crete would be defeated anyway.
It would take a long time to finish off the little bits of Humanity, probably a few centuries, but the end would be inevitable. Once houses finish each other, the Nomads will likely not lose too many battleships as the survivors have less and less to fight with.
If a sizeable portion of the Bretonian government knew and was able to hold out long enough to build sleeper ship(s), then perhaps we do escape and start over. Otherwise humanity is gone for good. I can't see a non house mustering the resources to build sleeper ships. The Outcasts and Corsairs, while small houses in their own right, likely couldn't do it either. The OC can't survive without Malta, and the Corsairs probably do not have the technology anymore, lost during centuries of poverty and starvation, unless there were plans on the escape pods that were preserved.
Of course, this is all opinion and conjecture.
*- By weakest, I mean that between them all, Bretonia is the least strong- that does not mean it is weak overall, just weaker than the others
