trade or action replay
my manns
You can't
Yes you can get other Pokemon that arent in pearl.
Pokemon indigo and Pokemon crater
I believe Pokemon world online is different from Pokemon crater.
after you beat the Pokemon league
Pokemon that know scary face and other moves or you can use dugtrio
Yes migrate them.
ditto
You have to battle other Pokemon with it.
there isn't a Pokemon ranch on Pokemon diamond, its a complete other game! there isn't a Pokemon ranch on Pokemon diamond, its a complete other game!
Pokemon can not transfer backwards. You can get Pokemon from other games to Unova, but the opposite is impossible.