Why do we think she's the daughter of Thomas Dacre and Philippa de Neville? According to Wikipedia, those two had 9 children, but none were named elizabeth. The only Elizabeth in the list of names would be the wife of Sir Thomas Dacre (not to be confused with Thomas Dacre, 6th Baron Dacre).
They had seven sons and two daughters:
* Sir Thomas Dacre (d. before 5 January 1458), who married Elizabeth Bowet, and by her had two daughters, Joan Dacre, suo jure 7th Baroness Dacre, wife of Richard Fiennes, and Philippa Dacre, wife of Sir Robert Fiennes.
* Randolph Dacre, 1st Baron Dacre of the North, who married Eleanor FitzHugh, by whom he had no issue. He was slain at the Battle of Towton on 29 March 1461, and attainted, whereby his title was forfeited.
* Humphrey Dacre, 1st Baron Dacre of Gilsland (d. 30 May 1485), who married Mabel Parr (d. 14 November 1508), and by her had six sons and three daughters.
* Ralph Dacre.
* Richard Dacre.
* George Dacre.
* John Dacre.
* Joan Dacre, who married Thomas Clifford, 8th Baron de Clifford.
* Margaret Dacre, who married John le Scrope.
https://en.wikipedia.org/wiki/Philippa_Neville
