I'm trying to see where you're coming from. You state, "Younger Jews are far more likely to be Republican than their parents and grandparents." I'd agree with "more likely" on that, but would quibble with "far more likely." But I'd say that the reasons behind that are more demographic than lack of bad experiences in youth with radio "evangelists." It's that younger Jews tend to be (1) less urban and more suburban and exurban than the immediately preceeding generations and (2) are and will continue to be increasingly more religiously observant as a group because of much higher birth rates and relative lack of assimiliation within the Orthodox subgroup.
I suppose you are saying that older Jews who had heard or been told about the "radio evangelists" of the 1930s are associating today's Christian Right with those old "radio evangelists" and thereby associating today's GOP with them.
Yes, Father Coughlin was very scary as an on-air voice of antisemitism during a time when Nazi Germany was on the rise in Europe, but I don't think he'd be called an "evangelist," but rather a rogue Roman Catholic priest. I never heard of Aimee McPherson being linked to antisemitism but I don't know all that much about her.
--- That's hitting it on the head. Even today my Dad's generation brings that up in conversations. I think both of your other points are pretty much accurate too. Don't forget that Jewish doctors are a pretty big subset too and they ARE FURIOUS with Obama. Some are clients and the conversations I have with them are almost vicious in their disgust.