Well, South Korea doesn't count because it is a very homogeneous state and doesn't have to deal with minority issues. I am very familiar with Korean culture and they are even more xenophobic than Han Chinese are. I have no doubt if S. Korea was a much larger country and had a large Muslim minority, they would be very discriminatory against that minority. So S. Korea having no "minority issues" doesn't really mean anything as they have no minorities really.
If you mean Kpop, yeah, they are very successful. It is basically a government driven industry to push S. Korea's brand image.
Yes, Russians are 100X smarter than the idiotic PRC when it comes to minority relations, communication and soft power.