Short answers, pulled from the story.
Lady Margaret Butler (born c. 1454, died 1539) was an Irish noblewoman born at Kilkenny Castle, daughter of Thomas Butler, the 7th Earl of Ormond. She is historically significant as the paternal grandmother of Anne Boleyn, second wife of Henry VIII, and therefore great-grandmother of Queen Elizabeth I of England.
Lady Margaret Butler's father was Thomas Butler, the 7th Earl of Ormond, and her mother was Anne Hankford. Her maternal grandparents were Sir Richard Hankford (c. 1397-1431) and Anne de Montagu.
Lady Margaret Butler married Sir William Boleyn before November 1469. Together they had ten children, including Thomas Boleyn, who became the 1st Earl of Wiltshire and Ormond and was the father of Anne Boleyn.
After the death of her father Thomas Butler, the 7th Earl of Ormond, Margaret and her sister Anne claimed to be co-heiresses of the Earldom. Their cousin Piers Butler, who had physical control of the Irish estates and backing of the Irish Council, contested this by claiming the right through the direct male line. The dispute was not resolved until 1528.
Yes. From around 1519 onward, Margaret was declared by inquisition to have suffered periods of insanity that made her incapable of managing her own estates. This formal legal process removed her control over her property.
Lady Margaret Butler was the last of the Boleyns to live at Hever Castle. After her death in 1539, the castle was given to Anne of Cleves in 1540. Her lands were subsequently claimed by her only surviving grandchild, Mary Boleyn, and Mary's husband William Stafford.