Just re-read your piece here with a few new thoughts. The Old Man and the Sea is all one-syllable words. Maybe Hemingway was hinting toward the decline of reading, that one than one syllable might cause too much hardship and if you want your books read in schools (big sales) then use shorter words.
All that to say that The Old Man and the Marlin is ruled out by the one syllable rule.
HOWEVER, I did notice that Marlin and Marlane are quite similar, and that maybe someone could pitch a Harlequin Romance novel titled the Old Man and Marlane. Just an off-the-cuff seed.
Thanks again for the read… and it was fun, again.