Yeah I guess another psychic is not really the best choice, and espy and xatu don't really benefit from TR anyway. Tyranitar could work in your team, but you don't need the SS because you already have hippo. Do you want to use Tar as a special wall or as a pursuit trapper? And after all, Tar doesn't really help against rain. And I assume you wanted a magic bounce user to prevent hazards?
Maybe you can use Tentacruel to counter rain even more, use rapid spin to get rid of hazards, and it is still a very good special wall. Plus it is a complete stop against Scizor with some defensive ev's. The only problem is that it's relatively fast, but with 0 iv's and negative nature it will be good enough.
Hope this helps!