Nothing because that cheat is fake. Sorry.
Shroomish is not available to be caught in the wild in Pokemon FireRed, it must be traded from Ruby or Sapphire.
Houndour can't be caught in firered so get one from emerald or colosseum.
Cubones can be caught on Seven Island.
You get one Johto starter in Emerald for completing the Hoenn Pokedex. You can trade them into FireRed. Unfortunately, Croconaws (along with Totodiles) cannot be caught in Pokemon FireRed. You must have one traded to you from Emerald.
you have to hack it.Arceus is a 4th generation pokemon, it can only be caught in diamond pearl or platinum.
no
Shroomish is not available to be caught in the wild in Pokemon FireRed, it must be traded from Ruby or Sapphire.
Chikorita cannot be caught in Pokemon FireRed. However, you can catch a Bayleef in Pokemon Colosseum, transfer it into FireRed, and breed it to get a Chikorita egg.
Yes, Grimer can be caught in Pokemon Fire Red.
train it to level 100!
Rayquaza cannot be caught in Pokémon FireRed and LeafGreen. Trading it over from Pokémon Emerald is required. You must first obtain the National Pokédex from Professor Birch after beating the Elite Four, though.
Rare Pokemon that can be caught in firered are: Moltres, Zapdos, Articuno, Mewtwo, Raikou/Suicune/Entei (depends on which starter Pokemon you choose).
Magmar can only be caught in Pokemon LeafGreen, therefore, you have to trade.
Snubble cannot be caught in firered to get one trade one from emerald or colosseum.
Houndour can't be caught in firered so get one from emerald or colosseum.
You'd have to trade it from FireRed or LeafGreen.
No because it doesn't exist.