Aha! Of course you are correct. I misread the relationship between Piers (her first husband) and Hugh de Audley (her second husband and father of her/their daughter Margaret, who married Ralph de Stafford, purported to be the First Earl of Stafford). Their son Hugh de Audley, the Second Earl, married Philippa de Beauchamp, and their daughter Katherine married Michael de la Pole, the Second Earl of Suffolk. In turn, their youngst daughter Isabel married Sir Thomas Morley, the Fifth Baron Morley. Their daughter Anne married John Hastings, and their daughter Elizabeth married Robert Hildyard. Their son Peter was the greatgreat grandfather of Ursula Hildyard, who married Sir
Richard Jackson (1570-1610) in 1596. These were the parents of Sir Anthony Jackson. Thus the marriage of Ursula to Sir Richard results in her Royal line to become connected to my Jackson line, descending branches of whom allow me to have a remote cousin relationship to both US President Andrew Jackson and to General Thomas "Stonewall" Jackson of the Confederate States Army during the US Civil War.
Thanks so much for your counsel!