...and this will affect Dart's Neiuport skin, how?
Well, she gets dressed in Horizon Blue and the overseas cap exchanged for a red kepi!
The whole mess is really one of cultural mis-translation! Hello Kitty isn't a cat in the sense that she's not a
house cat. That's why Hello Kitty can have a pet cat, which is a normal animal. Sort of like how Goofy isn't a dog, but Pluto is.
So Hello Kitty is either a cat that is sentient and acts as a human (which means she's not really a literal representation of a cat), or a human in the guise of a cat (which is just stupid).
The whole issue is pedantic in the extreme. Nobody ever pressed Walt Disney on whether Mickey Mouse was really a mouse, since he can talk, drive, pilot airplanes, operate locomotives, performs magic, has a pet, a girlfriend and wears clothes - something actual mice can't actually do; he'd say not to worry about it and buy more t-shirts and figurines of the character.
So is Hello Kitty a cat? Strictly speaking, no. She's a cartoon character.