I'm just jumping into this discussion now, and I have a few of my own nitpicks:
RE: Interstellar war being made impossible by distance:
Likely true in the early days of your setting, but by the 50C, with thousand year lifespans and ships traveling at .95c, it becomes much less plausible. With a thousand year lifespan, each year would be approximately equivalent to a month for a person with an 80 year lifespan. At .95c, you also have a gamma factor of approximately 3.2, which means that a traveler experiences less than a third of the time an outside observer sees a trip to take.
(You get this wrong in the section on interstellar travel, which says "a trip that appears to take 10 years to an outside observer takes only 1.6 years for the passenger". The formula for the gamma factor is 1 / sqrt (1 - (v/c)^2), which for .95 c works out to 1 / sqrt (1 - (.95)^2) = 1/ sqrt (0.0975) ~= 1 / 0.31 ~= 3.2. The numbers in the interstellar travel section suggest a gamma factor of six, which would require a speed of approximately 0.986 c)
Anyways, with a speed of 0.95c, a there-and-back trip to Alpha Centauri will take, as seen by the traveller, a fraction of his lifespan equivalent to about an 80 day trip for us. As seen by his friends sitting back at home, it will take about 260 days equivalent. This is fairly close to the timescale (measured as a fraction of lifespan) for travel between the belligerents in the American revolution.
And given that your quickships power themselves with "the dark energy found in the void", it doesn't seem plausible that war should be any more limited by resources than it ever has been. (Plus, energy should be even cheaper than you're making it, given that restricting the technology that's being used to power these ships from being used for stationary generators isn't really plausible).
You probably won't have wars raging across all of Incatena space (which would still be a bit too big for that), but I can't see wars not happening between neighboring systems given the situation you describe for the 50C.
RE: Coldsleep on interstellar voyages.
Given that you mention having free-floating space habitats that seem to be self sustaining and not to have any dependencies on inhabited planets, I find it unlikely that coldsleep would really take off, especially for shorter voyages. It is of course, likely that you'd cut a lot of the stuff that would go into a habitat out of a ship, but if a person can comfortably live in a habitat for their entire life, they'll likely comfortably be able to live on a ship for a few years.
You say that "sensory deprivation is the kind term for the level of excitement on a long space journey", but with stuff like "the Vee", there should be no risk of boredom. Even modern storage technology is good enough that an archive of Wikipedia could fit in your pocket, so a moderately-sized room on an interstellar ship should be able to host a Vee environment, that, if not as large or diverse as you'd get when connected to a planetary network, should be quite satisfactory for the passengers.
You say "It’s no longer necessary to guess or moralize when confronted with economic or political problems." But even if you have a system that allows you to perfectly predict the sociological or economic results of a given action, or better, a way to determine the course of action that will lead to a desired set of results, you're still faced with the fact that there may well be differences of opinion on what the desired results are. Your problem with abuse by authoritarians may be somebody's response, according to the principles of socionomics, to a problem you refuse to see, especially if two different groups have diametrically opposed goals on a certain issue. You might see an ideal state of affairs. They might see a profound social problem in that you even *think* such a thing could be an ideal state of affairs. You may have a way, via socionomics, to solve the "problem" of people that think like that, but they may have a way, via socionomics, to solve the "problem" of people that think like you, and it may just come down to who has more leverage to apply socionomic principles on society. You may have a socionomic way of arriving at a compromise that will satisfy the vast majority of both groups, but a compromise might not be a desirable goal.
Look at it this way: The problem with Hitler was his perception of the *existence* of a "Jewish Problem", not the quality of his solution. The final solution would have been a good one *if there was a problem*. Not all problems in politics and economics are as severe as Hitler slaughtering the Jews, but the principle is the same: The best scientific way of arriving at a given set of results won't help you if your desired results are wrong. Abraham Lincoln, armed with socionomics, might do ten times the good that the real Abe Lincoln did. Adolf Hitler, armed with socionomics, might to ten times the damage.