You'll note that most of the criticism I made came regarding the physical features of the Marina design, predominantly the hair, and the most any of the detractors have said regarding her skin color in the uncolored pictures was me where I said I don't mind that all that much. If I'm gonna point out issues with the literal skin color I'd point to the colored picture on page 6, and all I'm gonna say about that is it's kinda weird the shade this artist used there is noticeably lighter than the art they used on page 1. That's weird right? What's up with that?
But let's put all that aside for a moment. Whitewashing is not just used for the literal lightening of skin, although that is a large and frequent way it winds up coming up. In this instance, it's because the author's interpretation of Human!Marina winds up removing nearly all the racial coding and characteristics of her regular design. Marina is functionally a black character, in narrative and in appearance, so in creating a design that effectively removes all of that racial basis, presumably out of pure ignorance from the artist using what they already know about character design, is not only kinda shitty, it makes her nearly unrecognizable. And that's bad in a purely artistic sense.
(Also, juan, what the hell are you talking about. Pearl's pointy tooth is a squid beak. Why would a human have a squid beak. And attractiveness is not a metric you can measure objectively but looking at the actual physical characteristics between the two designs there's very little actual deviation.)