1) Volga Germans were not Nazi. They didn’t do it. The following link suggests that the Soviet Volga Germans fought against the Nazis in World War II. http://www.twcenter.net/forums/showthread.php?t=255347.
2) Any inquiry wouldn’t apply to U.S. citizens that have been in America for some time.
3) You may get some varied responses from people from other village areas. It may be Germans from the Black Sea area or from Slovakia that would say, “It may not need to matter to you.”
4) They may have some holds, health issues or work problems if it pertains to any “Nazi heritage or claims.”