Excellent observations! It is possible he did the minimium to graduate and spent the rest of the time with the likes of Bill Ayres and/or radical Isamists.
As soon as I heard that George Stephanopoulous graduated the same year I did (’82), I checked with another friend from the same year to see if he knew him. He said, “Yeah, he was in my fraternity. We called him “Silent George” because he never really said anything and was always off at political meetings.”
I offer this as data, nothing more. GS’s picture is in my yearbook, and it didn’t take me long to find someone who knew him, even though he was off campus a lot. Barry must have been one hell of a recluse for no one to remember him.
If BO had willing sponsors, it would be easy for him to have graduated without attending any classes or even showing up on campus.