How do you get Kanto starters in Pokemon HeartGold?

Answer 1

The Kanto starters are obtained after collecting all 16 badges and defeating Red
you gotta beat both Pokemon regions gyms and elite four all 16 gyms and all 8 elite four members then go to Prof. Elm and Prof. Oak for the johto and hoenn starters
Yes, but you need to defeat all the gym leaders in both johto and kanto, and you have defeat Red.

Once you finish that go too Professor Oak in his Lab and you get too pick a Kanto starter