Wow, DC. I was so relieved to finish GF's Revenge that I didn't even consider the idea of a third Winegardner book.
You are so right about Winegardner conveniently giving Fredo an heir. The worst part of it is that, given the age of this alleged child, he could set it after the events of GF 3.
Sonny's bastard son vs. Fredo's bastard son
He must be stopped !