The Irish came to American because when they didnt have any food (Famine) They were in serach of land and food. There were so many of them, they were looked down upon.
No, Ireland remained neutral during the second world war, though astray bomb or two was dropped accidentally by confused German luftwaffe pilots thinking they were over Brittain!
It would rather be Irish than it would be German. In Germany you barely see names beginning with "C" followed by a vowel and the combination of the letters "gh" is well known in Irish names.