Yes can you catch rayquaza and what Pokemon can beat ghost Pokemon ice..

You can catch rayquaza on the sky pillar.

Sydney: use's dark type pokemon. You need a good fighting type like Blaziken or machamp.

Pheobe: use ghost type Pokemon, you need a goo pyschic/ghost or dark type Pokemon that knows psychic and shadow ball.

Glacia: use ice + water type pokemon. A good fire and fighting type Pokemon will do the trick.

Drake: use's dragon type pokemon. The move ice beam will do the trick execpt for his kingdra which is water + dragon, the moves like thunderbolt,outrage,dragon claw and dragonbreath will do the trick.

Champion Wallace: uses water type Pokemon, electric and grass type Pokemon will do the trick.

Pheobe first Pokemon is dusclops and it will use protect, use a 2 turn move like fly,sky attack anr solarbeam.

Drake first Pokemon is shellgon, it will use protect so use a 2 turn move aswell.

Yes,Rayquaza can be caught. Ice Pokemon are weak to Fighting,Fire,and Steel-type attacks. Ghost Pokemon are weak to Dark,and Ghost-type attacks. Dragon Pokemon are weak to Dragon,and Ice-type attacks. The Emerald E4 are Dark,Ghost,Ice,Dragon. Then the champion is Water. So you may be thinking about FireRed/LeafGreen

To beat Sidney(Dark) Bring a fighting type
To beat Pheobe(Ghost) Bring a ghost or a Dark Type.
To beat Glacia(Ice) Bring a Fire,Fighting,or Steel type.
To beat Drake(Dragon) Bring a Dragon of your own,or a Ice.
To beat Wallace(Water) Bring a Grass type.

Hope I Helped

1. Yes.
2. Ice-Fire, Rock, Steel,
Ghost-Ghost, Dark,
Dragon-Dragon, Ice,
Rock-Steel, Grass, Fighting, Water,

The Elite Four is Dark, Ghost, Ice, Dragon.The champion is Water.

1.Yes you can catch Rayquaza in this game.

2.Ghost-Physic
Ice-Fire,Electric
Dragon-Ice,Dargon
Rock-Water,Grass,Fighting

3.Try useing a Electric Pokemon,most of his Pokemon are water.