It wouldn't be even remotely fair as Warwick and Nick Nack are both fit for their size while Fred is a misshapen ball of puddy. A more interesting match-up imo would be Fred and Eric the Midget in his prime. Were this a just world there could have been a PPV event where the two were plopped on a bed and the first to wrestle the other one off would win a prize.
Side note, based on watching the public behavior of two of them, I believe all midgets with severe congenital disorders are terrible people. No fault of their own really, you would have to have the patience and wisdom of a Tibetan monk to be dealt that hand in life and not end up being an enormous asshole.