Interesting threory, though I don't think so, personally.
Just a related note--I really like the character of Captain Syrup. I think it's cool that Wario has someone to compete with when it comes to greed and power! It's evil vs. evil! Oh, I guess he has Rudy, the Evil Clown from WL3, too.
And I think Pauline broke up with Mario, myself. While she loved him for saving her from DK, she had a premonition that Mario would go on to have more dangerous adventures, and decided to call it off. Thet remained freinds, though she wonders where he's gone off to. He hasn't been seen in Brooklyn for quite some time...
Well, I got a little off the point, so I'll bring it back now. Are Pauline and Cap'n Syrup the same person? We may never know for sure...