Short answers, pulled from the story.
The Khanate of Kazan existed from 1438 to 1552. Ulugh Muhammad assumed the title of khan in 1438 following the collapse of the Golden Horde, and the state fell to Russian forces on October 3 after two months of destruction in 1552.
Ulugh Muhammad founded the Khanate of Kazan by usurping the throne with assistance from local nobility in 1438. His son Maxmud finalized the transfer of authority around 1445, solidifying the new political order and ending Volga Bulgaria's direct rule.
At least five languages were used in daily life including Tatar, Chuvash, Mari, Mordvin, and Bashkir. The written form was Old Tatar language which became the favored state tongue for administration and literature.
Khans were replaced nineteen times over a span of one hundred fifteen years throughout the history. There were fifteen reigning khans with some ascending the throne multiple times during periods of instability.
Forces of Ivan the Terrible laid siege to Kazan in August 1552 operating from the fortress-island of Sviyazhsk. On October 3 after two months of destruction the Russians entered the city and put most defenders to the sword before forming rebel governments that ended by 1556.