What it means to be a mixed-race model in Japan
http://edition.cnn.com/style/article/rina-fukushi-japanese-hafu-models/index.html
What made me laughed is that CNN acknowledges "Hafu", which Japanese people intend to pronounce "Half".
How biracial actors or actresses are treated depends on their ancestrals' nations.
If they are in Europe, American, or Australian continents, they won't be backlashed. But, if they are in Korean Peninsula, they have to pay attention to their behaviour.
When they talk about political issues lied between Japan and South or North Korea or are rumored to have done bad things, they will be enemies of Japanese citizens especially on the internet.
So, it's difficult to generalize how foreigners are treated in Japan.