Hmm.... thinking about it, except for Tyranitar and Metagross, all his Pokemon are weak to Ice. In fact, all of them except Hippowdon have a 4x weakness to it. Try ice and ground types for the Tyranitar and Metagross. I think Mamoswine would be the most effective Pokemon, since it has an ice and ground typing. I remember you can obtain one by leveling up a Piloswine with Ancient Power, or sometimes in the rustling grass at Giant Chasm you can catch one, but leveling up Piloswine is more effective.
Edit: I accidentally skipped Abomasnow. Try using a fire type, or a flying type, like Moltres for that one, or if you don't use legendaries, Charizard for that situation. Happy to help.