If there were as many Jews as Rigg suggests then chances are at the very least several thousand were Jews on their mother's side. Chances are at least some were not raised as Jews and even if they were raised as Jews they could still have managed to get into Hitler's army.
You can logically conclude that Halachally-jewish people will not consider themselves half-breeds. The Halachally-jewish people exlude the paternally jewish people - I know because I've experienced it.
By the way this whole thing is a non-issue, because in the days of the Patriachs, it didn't matter what the mother was. And the whole mother-determining jewishness rule was a rabbinical innovation of the middle ages.
For instance if there really was maternal transmission of jewishness solely, there would be a tribe named after Jacob's daughter Dinah.