I get where you’re coming from. Plus their facial features and everything else also don’t quite matchup with darker ethnicities. (Like how people from India have very specific facial features, Native Americans, African American, etc)
I suspect this might be why the author isn’t using the correct skin tones. If the author doesn’t know how to make the body features match the more natural darker skin tones- without the characters seeming stereotyped- then that could be the reason why the author is avoiding it.
Also, keep in mind this is the same author who gave people, natural purple and blue hair and weird baby bird pinfeather eyebrows. They might just like quirky looking people. (Pluton’s hair is a thick main of pure white that needs to be featured in a L’Oreal commercial. Actually, there’s a ton of young people (in this series) with luxurious locks of long white hair.)

Call me the woker but i feel like its lowkey abit strange for characters with darker tones to well,,, not actually show brown/black skin tones(bit confused to why they grey) Like I KNOW pulton is here+ plus these guys and I greatly appreciate their existence but I JUST FEEL ITS ABIT OFF?? Like i feel like its abit strange for nearly no character in the story having melanin and instead the author opting for another colour? This isnt like a SERIOUS SERIOUS critique but i am abit tired of like "omg the top ten r from all around the world!!!" and feature like 3 differing aspects when it comes to the body (including skin tones). If there is characters who have like more "natural dark skin tones", please correct me because i just feel like its a odd choice- BUT ITS NOT A REALLY BIG DEAL I JUST WANTED TO ASK THIS