Felix was never married in the books. After getting snacked on by the shark, he retires to work for Pinkertons, then is recalled to active duty by the CIA in Thunderball. AFAIK, that was his last appearance in the original books.
As for Joe Don Baker? I'm sorry, but he'll always be Mitchell to me.
Mitchell....heart pounding...Mitchell!! Blood clotting....Mitchell!!
I have trouble swallowing Joe Don Baker as Jack Wade, CIA agent... I still see him as Brad Witticer, arms dealer from The Living Daylights... HEY! that was Dolph Lundgren's first movie!