I finally sat down and created a matrix/checklist incorporating all of the cards I know of from the three subjects [baseball, boxing, entertainment] into a deck of cards. The results were very interesting. The baseball, boxing and entertainment cards fit together perfectly. I have evidence of the existence of 13 boxers, 4 ballplayers and 10 entertainers and not one overlapping card. Here is the matrix:
I was initially hesitant in putting the entertainers with the athletes because the boxers had an extra line of writing but after seeing how the the cards mesh, I am no longer concerned. In my mind the seamless fit of the various subjects I can confirm is very strong proof that this issue was a mixed subjects issue that will eventually be found to comprise a full deck of cards. I have scans of every card on the matrix, BTW, so I am certain that all of them exist.