By Trading By breeding: Breed your Starter and giving them to friends for their Treecko, Torchic, Mudkip, Turtwig, Chimchar, Piplup, Totodile, Chikorite or Cyndaquil egg. Basic: You need a Link Cable or Wireless of you are going to complete the Pokedex.
cheats
No.
You can't, but you can get them all through the global trading system or gts.
its impossible without cheats
cheats
You have to complete your pokedex the oak gives you a call
1: Get all starters with trading
It is not possible to get all three starters in Pokemon LeafGreen without trading. This was an intended mechanic to encourage interaction between players.
only with cheats or by trading
Either through the wi-fi center in jubilife center or trade one of the starters to another DS then restart your game and get a different starter and repeat. So start>get starter>trade>restart>starter>trade> restart get last starter and re-trade starters back. It's complicated and long but worth it.
No, you can only get all starters without trading in Pokemon yellow, but Leaf Green is a newer version of Pokemon green, so it's impossible.
That's impossible.