Mean look will trap them, then taunt will keep them at bay. Nice Idea. I would suggest using the move spore to guarantee sleep on them, keeping them from using roar. Umbreon is great for defense, but if you want to get them with great power, I'd use Absol, who can learn both mean look and taunt, but also has false swipe, a very helpful move. Fast balls (when trying to flee), ultra balls, and dusk balls (at night) work wonders. If you transfer a master ball from a different game, it's your for sure.