There isn't a single specific term that encompasses all of those diverse ethnic backgrounds. People with mixed ethnic backgrounds often identify with multiple aspects of their heritage. They might describe themselves using a combination of the different ethnicities they are part of, or simply identify as "multiracial" or "mixed race." It's important to use respectful and accurate language that reflects the individual's background and self-identification.
But I think it would be:
Half Kenyan/
Half Ni*erian/
Half White-Chinese/
Half Korean/
Half Japanese or Nipponese/
Half Spanish or Spaniard