Short answers, pulled from the story.
The Oklahoma City Thunder is owned by Professional Basketball Club LLC, an investment group headed by Clay Bennett. The group acquired the franchise in 2006 when it purchased both the Seattle SuperSonics and Seattle Storm from Howard Schultz's Basketball Club of Seattle.
The relocation followed the failure of Seattle's Basketball Club of Seattle to reach an agreement with the city over a $220 million publicly funded expansion of KeyArena. After that deal collapsed, Howard Schultz sold the SuperSonics to Professional Basketball Club, which moved the team to Oklahoma City for the 2008-09 season.
Professional Basketball Club sold the Seattle Storm on the 8th of January 2008 to an ownership group consisting of four Seattle businesswomen. The sale kept the Storm in Seattle while the SuperSonics were relocated to Oklahoma City.
The Oklahoma City Blue is the NBA G League affiliate of the Oklahoma City Thunder, owned by Professional Basketball Club. The group purchased the team, then called the Tulsa 66ers, on the 31st of July 2008, making the Thunder one of only three NBA teams at the time to directly own its development league affiliate.
Clay Bennett has led the group since its founding. Former members include Tom L. Ward, G. Edward Evans, and Aubrey McClendon, who died on the 2nd of March 2016. In April 2014, George Kaiser purchased Tom L. Ward's interest, and Jeffrey Records Jr. sold part of his stake to Bennett.
No. The Oklahoma City Thunder was the third NBA franchise to relocate during the 2000s. The team began play under its new name in the 2008-09 season after Professional Basketball Club moved it from Seattle.