You need the Rainbow and Aurora Passes, both of which were only given away at Nintendo events. Or you could use an Action Replay.
You cannot get to Fire Island on Pokemon LeafGreen. Fire Island is a setting exclusive to the second Pokemon movie, Pokemon the Movie 2000.
Four Island is a location in Pokemon LeafGreen. To start the journey there, you need to have at least 60 different Pokemon.
on cinnabar island
Cinnabar Island
on cinnabarb island
4 island.
No, but you can breed them on island 4.
The Pokemon day care for Pokemon Leafgreen/Firered is on island 4. You have to beat the elite 4 and get the machine on island 1 working to go there.
island 3
seafoam island
of course!
on a island