Do you think Howell’s three “general categories” of ethnic minorities in Japan m

Do you think Howell’s three “general categories” of ethnic minorities in Japan make sense or would you group them differently?
Do Japan’s ethnic minorities complicate the narrative that Japan is an ethnically homogeneous nation or are they “the exceptions that prove the rule”?
How is Japan’s way of dealing with multiculturalism similar to or different from other countries?
Is it possible for ethnic minorities in Japan to escape the “paradox” of either assimilating or not having a voice in Japanese society?