Keldio is not yet available. It will be a future event on wifi most likely. Keep a eye out on Pokebeach.com or bulbagarden.net
No, but there's something called Pokéthlon.
Yes. You find zekrom in Pokemon white and the white Pokemon in Pokemon black.
You get strength in Nimbasa City in a building there. I am not positive on where it is exactly, so talk to everyone in the buildings there and you will find it.
You can't find a snowrunt in pokemon black and white.
were to poochyena in pokemon black? :)
There aren't swarming pokemon in pokemon black.
You can find Kyurem in Pokemon Black at Giant Chasm (Interact).
You cannot find Celebi in-game in Pokemon Black and White. You must get it from the Pokemon Black and White Tour.
Unfortunately, you have to use poketreansfer or cheat. You can't find it in Pokemon black.
you cant- only the fifth generation Pokemon are on Pokemon black
You can't exactly 'find' Mew in Pokemon Black or White. The only way to obtain Mew in the game without cheating is to transfer it from an older Pokemon game, trade with someone on the GTS (which may be hard since everyone asks for impossible to get Pokemon), or somehow find it in the Dream World. :)
you can't find haunter in Black