to add on to this - would allied POWs of clear german descent be treated any differently than their fellow POWs?

Most of the Volksdeutsche were located in Poland and Eastern Europe, and they were treated by the Nazi government as German citizens. This gave them many benefits (Volksdeutsche received a lot of financial benefit from the confiscation of Polish and Jewish property), but it also meant that they were subject to conscription. As such, thousands of them fought as regular soldiers in the war. I'm not aware of a Volksdeutsche Wehrmacht soldier being tried for war crimes, but some Volksdeutsche non-combatants were tried as criminals after the war in Poland and other countries. In Yugoslavia, many were killed as reprisals against German policies.

I am guessing you're specifically asking about American Volksdeutsche like the one in Band of Brothers. Unfortunately beyond that anecdote (present in the book as well as the show and confirmed true by the soldier at the time that BoB came out), I don't have any information.