The Seven Races can't breed the same way that traditional human "races" can.
Sure, new races would form after thousands of years; but directly after the seven Eves start making babies? The only explanation is that the genetic engineering programmed the traits of each race so deeply that race-mixing was just not as easy as it was for traditional human "races." When a black parent and a white parent have a child, the child is usually distinguishably "mixed." But for the descendants of the Eves, a child will *usually* be born just as one race or another; just as a blue eyed parent and a green-eyed parent don't make a turquoise-eyed child, the child of a Moiran parent and a Teklan parent will *usually* be either Teklan, Moiran, or some other race in the family's history. "Mixed" people do exist, but they are an anomaly.
It is plausible that this rule for the races would have been intentionally programed into them by Moira, because after all, it was part of the agreement that each Eve get to choose specific traits of her descendants. They would naturally need to find a way to keep said traits ingrained into the descendants, and preventing them from being bred out in the first few generations.
The protagonists of
REAMDE were among the first Pingers.
Dodge, Zula, Csongor, Sokolov, Oliva, Yuxia, et al are plenty badass to be among the few survivors of the Hard Rain. Since their previous adventures took them on boats a lot, it's plausible that they'd have joined the submarine groups. Zula and Csongor, Sokolov and Olivia, and Yuxia and Seamus were among the first couples to being repopulating humanity underwater.
Heroes from Cryptonomicon, Zodiac and TheBigU may also have been among the Pingers or Diggers.
The events of
REAMDE explain the lack of Islamic terrorism in "Seveneves."
One would think that if the end of the world was announced around the globe right now, terrorist attacks would skyrocket, as jihadists rushed to earn their 42 virgins before their time was up, and as certain nations took the opportunity to nuke Israel, the U.S., and all their other enemies. Islamic terror is even addressed in "Seveneves," in the backstory of Camilla. So why weren't explosions going off long before the Hard Rain began?
Because of Richard Forthrast's defeat of Abdallah Jones, a few years earlier. Jones was so important to the entire network of Islamic terror, that in defeating him, Dodge, Zula and the rest ended up unraveling Islamic terrorism around the globe almost overnight, so by the time Doc Dubois announced Armageddon, there weren't enough terrorists left to do any significant damage.
Julia's arrival was the result of Pete Starling's conniving behind her back, and her behavior afterwards was a side-effect of his death.
Starling also seemed to be very much a power-behind-the-throne in the administration, so he might have had enough pull to round up a "spare" X-37 and have it positioned at Wallop's Island (the nearest launch facility to DC) in the immediate run-up to the Hard Rain without JBF knowing/noticing. Considering that the Presidential seal was printed off on an almost-out-of-ink printer and there apparently weren't even harnesses in the seats and their aluminum cylinder had no engines or anything, JBF doesn't seem to have planned her emergency escape ahead of time. The latter could have been down to the 20 days knocked off the timetable, but the former (as well as both of them still being dressed for DC) strongly hints at Starling having kept JBF out of the loop if only for the sake of plausible deniability. Facing down imminent death as the other option on the table, she jumped at whatever Pete had thrown together.
As to her behavior, in addition to issues with her being an instinctive politician, absent Starling "keeping a lid on her" and moderating any moves she wanted to make, she basically panicked and (unfortunately) was charismatic and skilled enough to sunder the Cloud Ark community.
