40 turns
Go to the Pokemon league and become the champion
There is no key it opens when you become a Pokemon champion.
There is not any dawn stone in Pokemon emerald, only in Diamond and Pearl. And the Pokemon that evolve from this stone don't appear in emerald/ruby/sapphire, they become available in Diamond and Pearl.
You cannot be a gym leader in ANY game.
The fastest Pokemon you can get is ninjask catch a nincada train it to level 20 and it will become ninjask.
You must have a Pokemon firered or leafgreen trade you a pidgey then train it to level 36 and it will become a pigeot.
certain pokeblocks can make Pokemon happier if your talking about Pokemon emerald or Sapphire, but generally the more you raise your Pokemon the happier they become.
raise it to lv 20 and it will become powerful!
the closest you can be to a gym leader in this game is setting up a secret base with your best Pokemon then mixing records
ditto can only be caught in emerald after u have become the champion behind the fossil maniacs house ditto can be caought BUT ONLY ON EMERALD
beat the elite 4, become champ.
Get feebas's beauty up to the max level train it one level and it will become Milotic.