i do not no
Get a kanto starter :p
In HeartGold and SoulSilver, she does not battle you - which might be one of the reasons why she doesn't have a starter pokemon. Instead, she has a Marill.
You can't
choose it as your starter pokemon
It's a starter pokemon.
Starter Pokemon at beginning of game
You can get it as a starter Pokemon or you can trade on the GTS.
In Pokemon Heartgold and Soulsilver you can get a Johto starter from Professor Elm, a Hoenn starter from Steven, and a Kanto starter from Professor Oak
By the GTS or trading with your friends
How can it?It never was and it never will.
Get any Hoenn starter you want. It doesn't matter.
You cannot get Mewtwo as a starter Pokemon. The only starter Pokemon available are Charmander, Squirtle, and Bulbasaur. There is no other way to get another starter Pokemon. Mewtwo can only be obtained at the end of the game.