use master ball if you haven't yet. if you have used it the best way would to use a Pokemon with sleep powder or sing then use a Pokemon with false swipe to get its HP low then use Ultra balls
First you got to catch him in Pokemon leafgreen or fire red and trade. Or you can use a gameshark. it lets you catch all the Pokemon from bulbasaur to deoxys.
You can't catch one anywhere in Emerald. You'll have to trade one from FireRed/LeafGreen.
Dialga Palkia, Rayquaza,Kygore and Groudon
In Pokemon emerald and other Pokemon games bad eggs are glitch Pokemon called missingNo. that will mess up your game if you catch them.
Mauville city!
you bring it to the scientist at the museum
cant cant cant
Get the Old Sea Chart and go to Faraway Island.
After beating the game it will appear northeast from pacifidlog town.
Aron evolves at level 32.
yes, get a male fire Pokemon and a female BLAZIKAN(rare beginning Pokemon) and bring to DAY CARE CENTER.
If you meant Rayquaza then I know where. He is in route 31 I think, before Pacifidlog Town.