well since the first one is a water and ice type i would either recommend a raichu or a zapdos at a high level.next is a rock type so if you picked a squirtle you can use your blastoise or a gyrados or a poliwrath.next is a gost type so i would use a phycic like a alakazam or another phycic.then a dragon type and i use a articuno at high level but since his first Pokemon is gyrados use that raichu or zapdos.last is your rival so use those Pokemon i just told you to use and have two Pokemon of your choice in there.
hope this helped
Seven Island if you don't include the elite four.
The best way is challenge the elite four with your Pokemon or a Pokemon holding exp. share. The better is to use gameshark codes for rare candies.
All you have to do is just keep going back and defeating the elite four!! $FR3CK$
You have to beat the elite four and defeat team rocket for the last time on four island, get the sapphire, and give it to Celio.
Poke breeders are trainers who after deafeting the elite four go to 7 island in firered/leafgreen and putting two Pokemon in the daycare and they have an egg
you know in every Pokemon game . THE ELITE FOUR!
No its not an HM in leafgreen.
Seven Island if you don't include the elite four.
Venusaur,Rapidash,Gyarados,Pikachu,Pidgeot and Dragonite
After you defeat the Elite Four.
train your Pokemon that's it.
Beat the elite four.
To open the Elite Four, you have to get all the Gym badges.
The best way to trade i guess wuld be to 'MIGRATE' from LeafGreen, in Pal Park to do this you need to beat the elite four and get the national pokedex
your strongest Pokemon
get some good pokemon with good move
Prof oak after beating the elite four.