I don't really have much on other native ethnic groups aside from the Ainu people, which as a minority group went through colonialist oppression similar to other native/aboriginal groups in other locations. Some site links: https://minorityrights.org/communities/ainu/#%3A%7E%3Atext=These+policies+and+legislation+aimed%2Con+their+traditional+economic+activities.

https://www.ff-ainu.or.jp/web/english/details/post-5.html

As for colorism, the culture trends conservative. I don't mean strictly politically, which it probably does too, but as in don't act out and stick with traditional values. Due to that, white skin is generally considered better looking and proper, and there is a negative stereotype for darker skin.

They are similar to S Korea like this, and there is a sort of blatant implied racism towards dark skinned and especially black people in the culture. There is of course some fetishizing of dark skin too, but mainly in a fling but don't settle down kind of way.

Some younger people are of course bucking some of these trends, and I'm not quite up to date as stuff in my own country, but it's definitely still there. There are people who have given personal experiences, some positive, some definitely not.