I just wondered if the equivalent of nazis researching baptismal records, etc. occurred in the USA with Chinese Americans being forced to find proof of their national origin or face being interned; indeed, are there any incidents of Chinese Americans actually being interned? I would guess there were very few, I mean literally only hundreds, of mixed-race children in the USA at that time, but how were such children treated? Were there any laws analogous to the nazi Nuremberg laws applied -- for example, Jews who actually practiced Judaism fared worse than Jews who were merely "racially" Jews -- did Japanese Americans who actually spoke Japanese have more problems than more assimilated Japanese Americans?
That appears to be the case. Maybe they didn't "have to" do this, but lapel buttons were issued to e.g Chinese-Americans. At the very least, it was highly advisable for other Asian-Americans to distance themselves from the Japanese-Americans.
Probably a few Japanese-Americans passed themselves off as non-Japanese, just as a few Jews did so in Nazi-controlled Europe.