Hi people!! I have beaten the elite 4 once, and have caught mewtwo and..

FIrst it's a gameshark. Go buy one at Walmart are Target. The only way to get to island 8 ans 9 is using a cheating device are going to a Nintendo Event. Jirachi can beobtained by tradint over from Pokemon Colissiem using a cheating device are Nintendo Event. They legendary dogs are look latios and latias it's random to run into it. But you onlyget one dog.

Ok first off a gameshark is acheat device that messes up your game.The only way to get to 8 and 9 islands is to go to a nintendo event.

1.You can only get one legendary dog,and it depends on what starter you choose.

Squratle-Riaku
Charmander-Suicune
Bubasour-Enti

Look for thelengendary dog in Kendo not on the islands.

2.Dexoys-You need to go to island 9,but you need to cheat to get there.

3.Jirachi-Use the Bonus disk that comes with Pokemon colisum,or cheat to get him.

4.You can't go to thoughs islands unless you cheat to get them.

I can anwser the legendary dog one after you beat the elite 4 they wil randomly pop up if you picked..

Squirtle-Entei
Charmander-Suicine
Bulbasaur-Riakou

The dogs come out randomly anywhere after the elite 4 deoxys and the ticket were last years downloads at Pokemon rox sorry no more not sure about jirachi

To get the 3 leg dogs is only a 25% chance you get only 1 depending on your starter here they are
Squirtle(water)- Raichou(electric
Charmander(fire)- Suicune(water) - you get them lv 50
Bulbasaur(grass)- Entie(fire)

You can trade Jirachi from poke sapphire,ruby,emerald or collisiem
You can trade different forms from different games but on leafgreen you need to go to 8 island with a gamshark "thingy"

I can tell you how to get the three legendary dogs, but I can't tell you how to get deoxys or jirachi without a cheat device such as a gameshark. To get the three legendary dogs on one game you must have 2 fire red or leaf green games and 2 wireless adapters because you get to only catch one of them depending on your starter. As for deoxys and jirachi I can only tell you where to find a gameshark or an action replay. You'll want to try ebay, EBgames, or codejunkies.com.