One pokemon per match? As in a 1 vs 1 Tourney? Well... A Counter-sash pokemon will ensure a victory against any Physical Sweeper...
Actually, Counter-Bliss w/ CM and Focus Sash could win it for you. CM against Special Attackers and use Counter-sash on Phys. Attackers. BAM, you win the Tourney.
I have to ask, what is FEAR?
Also, I assume Explosion is an autoloss, right? Otherwise, you can always go for the comedy option of draw every round.
Beyond that, looks like Mekkah pretty much summed up the options. The only other thing I can think of is some kind of painful stalling death by Toxic or other junk, but most of those are going to lose badly to a lucky CH.
Since the chance you miss all 8 out of your Sheer Cold shots is about 5.7%, I'd rather replace Mind Reader with something else that helps against any of these counters. I can't think of anything though, so maybe that is the best choice.