If FMD and Madelyn had “horizontal relations” that does not lead to being Zero’s parents. Apparently he was wildly promiscuous. I am not going to read Cashill’s book, since you have, maybe you could give a couple of hints about his “ample” evidence. A poem doesn’t do it. Which may or many not reflect truth, anyway - if she had so much money, why did they live in a little apartment, why didn’t they own a nice beach house?
Traveling was a priority for Madelyn as shown here:
“As you can see, we live in an apartment instead of a house….But I think we could have done the other if we had wanted. But I traveled, you know, and spent money on the kids – the kids and TRAVELING were priorities.” (From Promise to Power David Mendell pg 36)