It makes no difference what Pokemon you use. As long as they are at a high level, and have strong moves. For example you could use a Golem with heavy hitting moves like Earthquake. Or you could use an Alakazam with strategic moves like Hypnosis, and then Dream Eater. As long as your Pokemon are at least level 45, and have strong moves, it doesn't matter who you use.
After you defeat the Elite Four.
get some good pokemon with good move
Defeat the elite four, Get all 386 pokemon.
Red is the boy playable character in leafgreen you don't defeat him because you are him.
Defeat the elite four and become Pokemon champion with 60 Pokemon recorded in your pokedex.
You have to get the rainbow pass which you cannot get until you defeat the elite four.
If you chose Squirtle as your starter Pokemon. Defeat the Elite Four and it'll roam freely in Kanto.
get all the super effective types including for last one and defeat everyone and save
your strongest Pokemon
You must defeat the elite four and the Pokemon champion then catch all the Pokemon which is only possible with help from friends.
It appears randomly around Kanto once you defeat the elite 4
They're on the FIFTH island.