Would Pinsir and Scyther make for good Psychic counters?
Water types will struggle with Drought Ninetails, SolarBeams everywhere.
Dragonite will probably be the toughest. Either Stealth Rock to break Multiscale, or status it. Besides the ones that you mentioned, would Defensive Gyarados be a good check? It can Intimidate, Thunder Wave, and phase with SE Dragon tail. Although much like Slowbro and Cloyster, Gyarados does not like Thunderbolt.