Potential of Hedonist/Satyriac Inbreeding & The Pug Debate:
The Hedonists are stated to live on an island no bigger than Iceland in the original text and have no overpopulation problem due to the females needing to mate with many males before pregnancy can occur. We can assume this was maintained perfectly during the 40 million year Qu reign but it is stated that with no pressures from the world that their evolutionary pace was glacial which so we can presume the hedonists lived carefree lives for hundreds of thousands of years after the Qu left meaning thousands of generations.
Most native Icelanders are at least 6th to 7th degree cousins with each other and that's just through a millennium of occupation. Many use an app to check that a potential date isn't a 1st or 2nd cousin hence their societal meme of "Bump the app before you bump in bed" Because of the population stability, by the time of the geographical upheaval that wiped most of them out; The Hedonists would very likely be heavily inbred. Inbreeding causes congenital defects through the activation of recessive genes and it is said that the surviving Hedonists that migrated to the newly emerged land were "Fast breeding freaks that had abandoned the reproductive quirks of their ancestors"
Evolution resulting from what would be considered defects is also mentioned with The Bug Facers that it was a congenital defect that caused the Insectophagi to reawaken intelligence and trigger dormant star person DNA. Considering what The Qu are capable of in terms of genetic manipulation it is possible that inbreeding with the Hedonists could have proved to be desirable rather than an aversion. When considering their limited population size on such a small landmass, it is highly likely that Hedonists probably often mated with close family members and could have even been the cause of their adaptability and evolution into Satyriacs.
The Sapient Satryiacs established a global state of presumably millions (Billions?) on a continent no bigger than Australia but would have managed to keep their population stable to survive as a race for millenia even before founding the Second Galactic Empire and colonizing other worlds before their eventual genocide at the hands of The Gravital. Presumably they found primitive ways of population control in their early days of sapience before turning to scientific approaches when they reached their point of modernity. This may be incredibly controversial but due to the Satyriacs small homeworld, ancestral history and extremely high promiscuity and libido; It is possible their race openly practiced incest and it wasn't a taboo in their society if the genetic engineering by the Qu ensured it wouldn't create problems for their species long term survival.
If one considers how modern day subjective prejudices are irrelevant to the workings of evolution such as The Bone Crushers socially practicing Coprophilia and how common incest is in nature. It wouldn't be that extreme to assume that a technically very human but still essentially alien society might have different views on close familial relations. Very controversial point; Inbreeding is believed to be more common in human society than most people would care to admit or know about and that even discounting abuse/non-consent, Some degree of consensual incestous behavior is believed to occur between close relatives in a given sample of a thousand people meaning there is statistically likely someone you know of and probably "At least one couple in every village"
The second point I raised is how often we are compared to The Qu in terms of selective breeding and the animal used as a prime example being the Pug. The Hedonists are labelled as the favourites of The Qu in the same way pugs are treated as our close canine companions despite the health problems they are riddled with through our enforced inbreeding of them. Comparing the Hedonists to Pugs is quite apt in that both are considered "Ugly Cute" deformities when compared to a healthy modern day Human being and Wolf respectively. One could argue that Pugs got the lucky end of our Qu-esque behaviour when we consider sentient sea life that we literally choke with our sewage and waste products with little care for their survival or suffering.