Yes.
You can buy Pokemon Black and White (JAP) almost anywhere in Japan. You could also order it from Nintendo's Japanese website, or perhaps Ebay.
No, Chaos Black is someone's hacked version of a Pokemon FireRed game. Nintendo and Pokemon never made the game, a teenager did.
No; because the newer Nintendo DS's unfortunately have a regional coding in place; so only games of the respective languages are compatible on that DSi.
No, Pokemon Black and White are compatible with all versions of Nintendo's DS line.
no there not ALL Japanese, you can get some at gamestop.
Yes, it is possible to trade your UK Pokemon from Diamond into the Japanese Pokemon Black version. However, you need to beat the whole game in Pokemon Black & White to be able to trade Pokemon from the other generations.
yes, even Japanese versions
Yes, you most certainly can!
That is not an offcial Nintendo Game, which means it is a fake. Pokemon Heartgold and Pokemon Soulsilver will be the newest games.
Since Pokemon white(or black, for that matter) was just released by NINTENDO, and action replay isn't supported by Nintendo, i doubt they've made codes for black/white yet.
The Nintendo 3DS is backwards compatible with Nintendo DS titles, so all DS Pokemon games and subsequent 3DS Pokemon games will work on the 3DS.
Probably, its just like trading a Japanese Pokemon to a English version, idk if the Pokemon name will be translated to English but you can trade i guess