The only way to get more masterballs without cheating is to have other leafgreen versions or firered or ruby or sapphire or emerald or Pokemon colosseum or Pokemon xd gale of darkness trade the masterball that those games get to leafgreen other than that you have to win the lottery in ruby and sapphire and emerald at lilycove city to get another masterball then trade it to leafgreen.
never.
You can't
yes
ok
No, only FireRed and LeefGreen
Deoxys is located in Birth Island.
Just get it to Lv.55.
Short answer: You don't.
no you cant they hatch in pokeballs
Action Replay (AR) you get 999 of them
Win the lottery at Jubilife city.
the best games in the world :D