William Dacre, 5th Baron Dacre - Family - conflicting wives

Can we clarify this any better?

Family

William Dacre, 5th Baron Dacre is said to have married Joan Douglas illegitimate daughter of James Douglas, 2d Earl Douglas of Scotland. However the evidence is not clear. He did marry a [[Mary Dacre Mary Dacre] “Mary”] who was his widow.

Conflicting references

http://www.cracroftspeerage.co.uk/online/content/dacre1321.htm

William [de Dacre], 5th Baron Dacre

• born c. 1357
• mar. Joan Douglas, illegit. dau. of James [Douglas], 1st Earl of Douglas
  • children
    • 1. Thomas de Dacre, later 6th Baron Dacre
    • 1. Joan de Dacre (b. 1374; d. 1456), mar. c 1397 Thomas Musgrave, of Hartley Castle (b. 1378; d. 3 Jan 1447), and had issue
• died 20 Jul 1399 (bur. in Lanercost Priory)
• suc. by son

http://www.thepeerage.com/p1743.htm#i17421

William de Dacre, 5th Lord Dacre was born circa 1357.1 He was the son of Hugh de Dacre, 4th Lord Dacre and Elizabeth Maxwell.1 He married Mary (?)2 He died on 20 July 1399.1.

He succeeded as the 5th Lord Dacre [E., 1321] on 24 December 1383.1

Child of William de Dacre, 5th Lord Dacre

• Joan de Dacre+3 b. 1374, d. 1456

http://www.thepeerage.com/p1743.htm#i17422

Mary (?) married William de Dacre, 5th Lord Dacre, son of Hugh de Dacre, 4th Lord Dacre and Elizabeth Maxwell.1 She was also known as Joan Douglas.2

Child of William de Dacre, 5th Lord Dacre and Mary (?)

• Thomas Dacre, 6th Lord Dacre+1 b. 27 Oct 1387, d. 15 Jan 1457/58