It is out in Japanese version (June 23rd), but not in English. Current UK release date is Autumn 2012
No, not yet
no
There is no official game yet, but there are rumors that there will be a Pokemon Gray version in a year or two, similar to Pokemon Platinum and Pokemon Crystal, as if it becomes real, it will be the third game in the Pokemon Black and White games.
Yes.
Black and White haven't been released yet...
Aside from the new Black Kyurem and White Kyurem, The Pokemon Company has yet to release any information on whether there will be any new Pokemon or not.
Yes.
no sorry
It was Pokemon Black 2 and White 2. The only Pokemon game that had a sequel.
no
There is not an event to get Keldo YET.
It has not yet been announced when Keldeo will be available for download in Pokemon Black Version and Pokemon White Version.