Generally speaking, anime are like furry: they are not intended to represent actual people in the real world... but the "inner persona" they represent. They are generally not actual humans in the sense of the biological primate ape called "sapiens-sapiens" (our species).... except for those with a big disease in the eyes. No, they are not "Caucasian" because Caucasian have wider eyes compared to Asians... anime have big eyes because that was popularized by Disney.
You can detect the supposed ethnicity by clothing and context: if you see a blonde anime girl with cowboy hat, that's an American girl. The same looking blonde girl without hat but a piece of clothing popular in Japan? She's Japanese.
2B is dressed as doll, she represent the "non-human" entity you can find in nature and Japanese seems to love a lot.
(Common example: dolls became alive, catgirl coming from actual cat, kitsune etc...)