Well, trading in a Minun could be an option so that you could use that special ability. That's a definite possibility, since all the battles in Colosseum are double battles. But frankly, the main storyline of the game is such that you could really use just about any Pokemon as long as it reached a high enough level. It's like the Game Boy games, where you can easily win with your favorite Pokemon, no matter what they are. (Well, almost; good luck using a team of Magikarps.)
If you really want to use it, I'd just suggest levelling up and trying to combo with something. I swept through most of the game and the double battle challenge using almost nothing but Feraligatr's Rain Dance (followed by repeated Surfs) with Ampharos' Thunder. You could try something similar here to take advantage of its decent Sp. Atk stat (it does learn Thunder naturally), or you could go for a pseudo-Ninjask idea with Double Team, Agility, Baton Pass, and a filler move (maybe Substitute for stalling?).