You have to trade over from one of the older games using Pal Park.
Just open multiple VBALinks, load your files, uncheck the pause when inactive, and go to the trade center. Sometimes some pokemon wont register as available for trade, I don't have a clue what to do about that, but this should be enough to help you out a bit, yes?
No, you have to trade an Adament orb over. Hope this helped!
Yes.
No, you can't trade with them.
Well, if you trade, it should go into your pokedex.
you need to trade it over from other Pokemon gamesYou'll need to trade for it from Pokemon Diamond, Pearl, or Platinum.
you have to trade over wifi or have a friend with Pokemon white and trade. you can only catch it in Pokemon white
Go to the union room on the second floor of the pokemon center, or trade over wifi.
no but you can trade them over with the item
You cannot get Rayquaza on Pokemon Diamond or Pearl unless you transfer it over from a Gameboy game using Pal Park, or trade it from HeartGold or SoulSilver. ~Lucario
Get one, trade to another game, start over, pick another, repeat, and get the other two back.