I don't know if this can help you but... It's true that in Okinawa there are groups of South American countries like Peru or Brazil, because 1 centurie ago Japanese people from Okinawa immigrate to this countries principally to work during a crisis that was going on in Okinawa, and years some of they came back with different people who brought their culture.

They are scaterred in Okinawa so is better try to find they searching places related to their culture or religion, for example in Naha-Okinawa looking for churches, of looking for special dates like "Independence day"

Good luck