Pidgeotto isn't the greatest pokemon in the world fearow is probably better because it has a higher attack than pidgeot so it can hit some good stab hits. Plus it learns drill peck. Dodrio is good too since it can use drill peck and tri attack which in my opinion is a great move.
Tauros, Raichu, Wartortle are pretty good in my eyes.
Parasect can be a bit better.
I don't play Kanto (I only have a 3ds so I am very restricted in the game department if I want the Kanto games,) so I don't know this but it might be easier to use a separate fire pokemon in the meanwhile, or some other good pokemon like dugtrio or Kadabra for example until you get rapidash.
Hope you succeed in beating the game and don't give up!