When the 13th volume of Kuroshitsuji was released, the manga had sold over 10 million copies in Japan alone. There have been no number counts released to factor in how many copies have been sold since, or how many have been sold in other countries.
As of now there have been no signs for any plans for Ash being in the Manga.
His age has never been told.
The new season of Black Butler/Kuroshitsuji 'Book of Circus' will air in Japan on July 10th, 2014.
Black Butler Season 2 has already been released both in Japan and the United States.
There has been no date given as to when Black Butler Season 3 will be airing on Netflix.
Yes, there have been black manga artists in Japan. One well-known example is Tony Morrison, who is a black manga artist living and working in Japan.
His name has never been given.
The exact ages of the servants have never been given.
Kuroshitsuji/Black Butler the Manga made its first debut in Japan in October 2006. It is still being released, and it is ongoing. Kuroshitsuji/Black Butler the Anime first premiered in Japan in October 2008. Since then Season 1 has been fully released, along with Season 2, 7 OVAs, and 2 Stage Musicals. There is at present no word of whether or not there will be a 3rd Season of the Anime, but fans are ever hopeful. So I would like to believe that the Anime is ongoing as well.
Finnian, also known as 'Finny' has not been given a last name as of yet.
Yes, Bleach manga 433 has been released.
Netflix has never said whether or not Black Butler Season 2 will be available through them. However, they did remove Season 1 for a while, and when the brought it back it now reads as Black Butler, Season 1. So, hopefully they are planning to add Season 2 as well!