We have thought about Dublin, as my husband flew through there once while we were dating and he said it was a lovely experience with CBP.
However, my husband spent several hours at Heathrow yesterday speaking with both American Airlines, British Airways and the CBP. American Airlines was super helpful and spent time on the phone (with who I do not know) seeking information. And they offered up the Dublin idea and the CBP officer said he would get the same answer if he tried.
So we've heard back from the US consulate this morning and we are in the process of filling for a boarding foil.
I am also waiting to hear back from our Senator.