Are there any "old-earthers" (as opposed to young-earth literal creationists) who also hold to a literal Adam & Eve, created ex nihilo?
I had trouble finding an article on the "Research & Reason" website that openly addresses this one way or another. The closest thing I found - the link "Who was Adam?" on the homepage - leads to this book on Amazon.com, which appears to suggest a long period of theistic evolution leading up to the sixth day, after which Adam and Eve, distinct individuals representing a new species (not derived from earlier hominids), suddenly appear - created by miraculous intervention and delivered into a literal Garden of Eden approx. 70,000 years ago.
Do I understand this correctly, as the position that "Research & Reason" is taking?
"Are there any "old-earthers" (as opposed to young-earth literal creationists) who also hold to a literal Adam & Eve, created ex nihilo?"
Virtually all old-earther literal creationists hold to a literal Adam & Eve, created ex nihilo. Those who don't are technically not OECs, but probably thiestic evolutionists.
"Who was Adam?" recounts the scientific evidence against evolution, arguing for the special creation (from scientific evidence) of all hominids and humans. I'm not sure where you found "theistic evolution" in that.
Much of the confusion comes from YECs who like to equate OECs with thiestic evolutionists. There are some major, obvious differences between them.