you cant there is no way you have to migrate or use an action replay
Cheat using an action replay
Yes by migrating
Yes.
No, you can't. Groudon is in soulsilver, Kyogre is in heartgold. The only way you can get it is trading, or migrating. Hope I helped!
Growlithe is one of the "version-specific" Pokemon. Growlithe is only available in HeartGold, while in SoulSilver you can only get Vulpix.
you cant get it without migrating.
You can only get it by migrating from emerald or trade from soulsilver or heartgold.
The only way is by migrating it from heartgold, soulsilver, etc
you cant, but if you beat the game and defeat Red in mount silver you can get 2 starters. I did this without cheating, i have a sceptile, charizard, and a feraligatr!! Great combo for basically any type! But honestly you can buy 3 games of heartgold or soulsilver then trade all the starters.
Well if you can't find it in the grass try trading with somebody or migrating it but there is probably no other way you can find clefairy in heartgold.
oh yes you can, i think because my brother caught an absol without migrating them
The reggis are not available in leafgreen you will need Ruby, Sapphire and Emerald to give you them.