Similar designs. -Richleu is basically Colorado with different colored hair and eyes. -Kawakaze design was based on 'japanese, but looks like half-european' given her blue eyes and wavy hair, two things that real native won't have. So when you swap clothes with Colorado, it won't give too much of mismatch because the clothes provide matching colorating with Colorado's color scheme. -Going back to point #2, Asakaze face has european traces on it. So if you swap her clothes with Richleu it won't create such dissonance as if you put Maruyu or Fubuki into it.