you can find chinchou in variuos places inside Mt.Coronet
You don't.
you can find it on route 220 using the super rod
Piplup does not exist in Pokemon LeafGreen or FireRed.
In Sapphire, there is Electrike, Manectric, Pikachu, Pichu(breeding), Raichu(evolve), Voltorb, Electrode, Plusle, Minun, Magnemite, Magneton, Chinchou, Lanturn, Zapdos(trade from FireRed or LeafGreen), and Jolteon(trade from FireRed and LeafGreen).
you can find chinchou in variuos places inside Mt.Coronet
You don't.
First of all you can't catch chinchou in leafgreen second of all you can't use the HM dive because its not a HM in the game so you need to trade one from ruby or sapphire or emerald.
By fishing on Route 220.
Chinchou is a Water and Electric type pokemon.
you can find it on route 220 using the super rod
Get a Chinchou, and evolve it. I'm not sure how you evolve Chinchou, but you can find them on route 27 if you go fishing with a super rod.
Piplup does not exist in Pokemon LeafGreen or FireRed.
No, you cannot find cyndaquil in LeafGreen.
you should go to gamestop
In Sapphire, there is Electrike, Manectric, Pikachu, Pichu(breeding), Raichu(evolve), Voltorb, Electrode, Plusle, Minun, Magnemite, Magneton, Chinchou, Lanturn, Zapdos(trade from FireRed or LeafGreen), and Jolteon(trade from FireRed and LeafGreen).
Do you mean Chimchar? If thats it no if thats not it the pokemon chinchou dosen't exist