Drop Haunter unless you can evolve him. Drop Pidgeot for a later game flying type when you can, like Aerodactyl.
Grab your game's fire type, Growlithe or Vulpix.
For a water type, your options aren't limited. Gyarados, Tentacruel, Poliwrath, Starmie, Lapras, the list goes on.
If you're willing to move the Raticate for a 6th member, I'd recommend a Psychic or Fighting type. Hitmonlee/Hitmonchan or Jynx/Mr Mime/Drowzee.
