Treeko>grovile>septile torchic>combuskin>blazkin mudkip>marshtomp>swampert.
Sorry, but the only way to get all the starters from Pokemon Crystal to Fire Red or to Pokemon Emerald is to get a gameshark and do it from there.
i think you have to complete it and birch will give you one
You can first collect all of the Pokemon for the hoen dex in Pokemon emerald you will get 1 of the 3 Pokemon gold/silver/crystle series starters then use the get all of the starters trick to get them all then migrate them to Pokemon diamond or pearl.
cheats
You can get it by transferring the Johoto starters via your Game Boy Advance to Pokemon Emerald
emerald isn't on there
You can never find the starters in the wild you can though find johto pokemon.
you get them by catching all 200 Pokemon
1. Milotic 2. Salamence 3. Flygon
catch....... BUT ONLY on emerald
you can get them by either filling all your pokedex in emerald and talk to professor birch and then migrating them or AR.
you have to complete the hoenn pokedex and then i think you get to chose 1