Short answers, pulled from the story.
Sir William Kingston (c. 1476-the 14th of September 1540) was an English courtier, soldier, and administrator who served as Constable of the Tower of London for much of Henry VIII's reign. He also served as controller of the household from 1539 and was elected MP for Gloucestershire in 1529 and 1539.
Kingston received Anne Boleyn as a prisoner at the Tower of London on the 2nd of May 1536 and, with his wife Mary, took charge of her during her imprisonment. He reported her conversations to Thomas Cromwell, and those dispatches are now regarded as among the most important evidence that Anne was entirely innocent.
Yes, Kingston took part in the tilting competitions at the Field of the Cloth of Gold in 1520 and was present at Henry VIII's meeting with Emperor Charles V in July of that year. The French Dauphin also reportedly took a particular liking to Kingston, as noted in a letter Sir Richard Wingfield sent to Henry VIII on the 20th of April 1520.
Kingston was appointed Constable of the Tower of London on the 28th of May 1524, at a salary of one hundred pounds a year. He held the position through much of Henry VIII's reign.
In November 1530, Kingston traveled to Sheffield Park, the Earl of Shrewsbury's residence, to take charge of Thomas Wolsey. Wolsey had reportedly been told by a prophecy that he would die at Kingston, and was alarmed at his arrival. Kingston was present when Wolsey died and rode to London to inform the king.
Kingston was made controller of the household on the 9th of March 1539 and was invested as a Knight of the Garter on the 24th of April that year. He also received the site of Flaxley Abbey in Gloucestershire following the dissolution of the monasteries.