Some remarks about the terms:

Black: When I fist heard or read that Colin Powell was termed "black" I thought that was a simple error. I my personal perception he was "white".

African American: That term might make a bit of sense inside the USA but I hate it on an international level of discourse. It has been noted with a mixture of amusement and scorn in Europe that a CNN speaker spoke about "African American" rioters in Paris (2 or 3 years ago). In such a context, the use of this term is simply a sign of US arrogance in my eyes.

Caucasian: I have never heard that term being used in everyday language outside of a science context. Recently, Russian neo-Nazis have started a racist campaign against "Caucasians". They mean, of course, those dark-skinned (from a North-European POV) people like Chechens, Ingush, Avars etc. They are white supremacists who look down on "Caucasians".

BTW, in German the respective term would not be African German but German African. That would now mean a German of African descent and at the times of my grandfathers would have been a German living in Africa. But the term Afrogerman is also in use.

Wolfgang