Take all the spacer K'kree over the years and let them breed having children acclimated to a space life. The inherent isolation of space travel would make them more estranged to normal society while seeking the camaraderie of like minds. Normalcy based on majority.
If the K'kree society become wary and unnerved by the alien behavior, there would be a growing rift. Spacers, especially newer generation K'kree, would still try to be part of ground society yet still find growing kinship with those who understand them, the older generation spacers. Retired spacers and their families might be attracted to shipyard and starports for the contact creating populations of tolerant minded. The Two Thousand Worlds may feel uneasy but they need those willing to do what normal, sane K'kree are adverse to do.
Imagine adventurers or just regular Imperial citizens in contact with K'kree vessels, especially military vessels, notice leaner, meaner craft and crew more adapted to space life compared to what history data recorded centuries ago. The only reason it may not happen is Hiver intervention to keep the status quo and a more harmless space faring neighbor. It may happen in the region of the greater Hiver influence while the wilder space between the TTWs and the Imperium could be such a breeding ground, say... Gateway?