You cannot find one on Silver, the only way to gain one is to Trade with somebody for all the legendaries in Pokemon Red, Blue, and Yellow.
You can only get a Vanilluxe cannot be caught in Pokemon black and white, the only way to get it is to catch a Vanillite or Vanillish and level it up to obtain a Vanilluxe. (Or you can trade with somebody who has one)
No, but you can trade Pokemon only in HeartGold to Black
Only if you give them to a Pokemon and trade the Pokemon.
Braviary (as well as it's pre-evolution, rufflet) does not appear in the wild in Pokemon Black version. You will have to trade with somebody who has Pokemon White version. Likewise, Vullaby and Mandibuzz can only be caught on Pokemon Black.
The only way to get Pokerus is by chance. I do not know the exact percent chance for finding it, but I do know that it is much more rare than finding a Shiny pokemon. the only way I can suggest you get it easily is find somebody who already has it and trade with him/her.
There is no limit to how many Pokemon you can trade, but you can only trade six at a time.
you can trade pokemon from heartgold to black but you can only transfer the pokemon in heartgold not trade it from black
maby,but the only way you can do that is if you trade with somebody a male/female eevee ,make them have the egg.
You can't trade Pokemon from Pokemon Gold to Pokemon Red, you can only trade Pokemon from Red to Gold and not the opposite.
You can only have Pokemon from Hoenn to Jhoto ONLY if you trade them.
You cam only trade Pokemon in emulators to another emulator. If you are trying to trade a Pokemon from the emulator to your actual game you can't