On the ranks, should be noted the Lyrans use German ranks even though the nation is actually mostly founded by colonists descended from Italy, Pakistan, Ireland and others but not really from Germany. The German influence in the LC is mostly a result of the Steiner family.
The CapCon is similar in this respect, though a bit differently. I think the original CC housebook notes that the CapCon's leadership caste/nobility is more Asian-descended than the State is on average but not 100% sure on this.
And for most of CapCon's existence, English was used for ranks. The Chinese ranks were introduced with the Xin Sheng reforms in late 3050s, so they've been in use less than 100 years.
Really don't think CapCon is more culturally uniform than any other state. Though having a police state makes enforcing certain appearance easier.