after beating the elite 4 go to mt ember on one island and get the ruby then take it to celio and he will give you the rainbow pass with that you can go to islands 4-7.
In the lost cave in island 5
Rapidash can be caught in the long grass after surfing from island one. The chances are about 5%.
With the Rainbow Pass.
no
Beat the elite four, Catch all the pokemon.
give ruby to cello
5 isle w/super rod
You can find a Larvitar in the Sevault Canyon on Island 7. It is a 5% catch.
You get an egg from a old man on island 5, one the water labyrinth
You have to use a super rod in islands 4 or 5. You can can catch it in Pokemon fire red and leaf green both.
try to catch horsea this Pokemon hold a dragonscale sometime but you only have 5-10% I hope it help you^^
get the national dex and beat the Pokemon leadge.Then go to island 5 then go through the meadow.