Current team weaknesses:
- Grass, Water, Ice
- Grass, Water, Fighting, Bug, Steel, Ground
- Water, Ground, Fighting, Fire
- Rock, Ice, Water, Electric, Steel
T-tar & Hippo are both weak to Grass, and the only thing that resists it is Bronzong. I would suggest Scizor based on that. Nidoking would also be adding another Water/ Ice/ Ground weakness to your team, which is not helpful. And while Scizor has a x4 fire weakness, but T-Tar covers that and sets up sandstorm anyway, so even if a Ninetails predicts it, Solarbeam wouldn't be that useful with no STAB and boosted sp.defence in Sand.
Considering that you have a x2 Water weakness on 4 out of 5 of your current team, I would suggest you replace Steelix or Aerodactyl with something like Storm Drain Gastrodon or Water Absorb Jellicent. Bronzong can only take so many water hits. Steelix is also not adding anything to your team, being slow and weak to the same things that the other Pokemon are and not giving any extra coverage.