the weather instadute
You can't. But you can migrate Pokemon from Pokemon Emerald to the Pal Park in Pokemon Diamond, Pearl, Platinum, HeartGold, or SoulSilver and transfer them into Pokemon Black.
You can't. Yoshi is not a pokemon.
by going to the village and talking to the Pokemon
you have to send it from emerald to platnuim to black
It can repel wild Pokemon upon use.
In Hell next to the man in black
You can trade it from Pokemon Emerald. In Pokemon Emerald, when you find Rayquaza, there is a small chance that it is shiny when you find it. Save the game right before you fight him and keep trying until it turns black. Then catch it and trade it to Pokemon Diamond.
It's in Hoenn region. You can play it on Pokemon Sapphire, Ruby, and Emerald
No. You have to either get it in HeartGold or SoulSilver or transfer it from Emerald.
Yes. You can trade all pokemon except Deoxys for some odd reason
You cant get every pokemon in Black and White without trading, unless you trade from Emerald/Ruby/Sapphire,Fire Red/Leaf Green to Diamond/Pearl/Platinum and/or Heart Gold/Soul Silver and trading the pokemon to your Black and White games from there. (Or you could just hack, but that can corrupt your game.)
A black Rayquaza is a shiny so you'll have to be very lucky for the Rayquaza you find to be shiny.