Go to other regions and talk to the professors sorry that's all i know
Chat with our AI personalities
Kanto/Hoenn-migration. Also for Johto but you must migrate from Emerald, after beating the league in Emerald, you go to the Safari Zone and there'll be a new area. In the new area you can find Johto Pokemon including the starters (the starters are EXTREMELY rare to find though.)
You can't.
I think once you beat every Gym Leader in Kanto, you go to Oak's Lab and he might give you Kanto starters. (Charmander, Bulbasaur, or Squirtle you choose which one.) If I'm wrong you can be mad at me if you want. <3
No you can not. You can only stay in Shinno in Platinum. On Pokemon Heart Gold and Soul Silver you can go to Kanto but not Hoenn and Shinno.
only if you trade them from red, blue or yellow