LOL @ potato pancakes! I'm pretty sure potato pancakes are a German thing, no matter what. Yum!

Maybe go over to Jewishgen.org and run your last names through their family finder database? German names can be Jewish and non-Jewish so it can be hard unless a Schlomo or some other obvious Yiddish names pop up in your family tree. Generally German Jews came to the US in the mid 1800s, as did a number of other groups (poor farmers for one because of the wars and general overcrowding). Obviously, they came around WW2 as well.

On Jewishgen, you can look up towns with large Jewish populations and compare your information there. There are also books of Jewish killed by the Nazi (yizkor books) where you can look for your names. Good luck!