Well then I don't really get the point of such threads because Nintendo doesn't really feature a huge amount of realistic human characters.
Their ARMS roaster is diverse. They should definitely add more variety to their Fire Emblem cast.
I guess that would leave Zelda and Super Mario where I don't expect new main characters to be added in the (near) future.
But if we don't count anthropomorhpic characters then is there a lot left to discuss about in terms of Nintendo?
I think skin sliders should be counted, but separate, since you can't really cite any specific cultural influence.
So yeah, without counting anthropormorphics, there's not much to talk about. Except for stuff like arms, FE, new metroid if it has more people, etc.
Arms and W101 had some diversity with clear cultural influences at least.
edit:
to your edit, I think characters like Marina are good too. I just have them separate from characters with actual cultural influences.
One one side I would have stuff like Misango or the Indian or French seeming guys from W101 (or Nadine for hyper realistic characters)
On the other side would be skin sliders in Xenoblade X, Splatoon 2, or characters like Elma or Marina.
And I put more importance in the first group.