Thank you, I got their marriage on the Scotlands People site. William's father was also William. William Senior married Mary Ross on 11 Dec 1840 in Duffus, Moray.
The index at SP lists five children of William Barron and Mary Ross, all baptised in (New) Spynie
Jessie, 20 April 1841
Mary Ann, 18 June 1843
William, 13 June 1846
Isabella, 2 May 1849
Angus, 5 June 1853
and FamilySearch lists one more, Margaret, born 15 February 1856 in Elgin. There's another couple with the same names having family in Aberdour at the same time.
The 1851 census lists the family at Bridge Street, Bishopmill, Elgin (which is in the parish of Spynie). From the transcription at
https://freecen1.freecen.org.uk/cgi/search.plWilliam Barron, head, married, 34, stone breaker, born Cromdale
Mary Barron, wife, married, 36, born St Andrews (i.e. St-Andrews-Lhanbryd, Moray, not St Andrews and St Leonards in Fife)
Janet (i.e. Jessie), 9; Mary Ann, 7; William, 4; Isobel, 20.
Mary Barron or Ross, aged 60, mother's surname Robertson, died in Elgin in 1872.
LIBINDX
http://libindx.moray.gov.uk/mainmenu.asp confirms this, and also says that William Barron, father of Isabella, Margaret, Jessie, Mary Ann and William, died in Elgin on 14 March 1881. He is listed in the Spynie Parochial Board (Poor Law) records.
Go to Scotland's Places and download the death certificates of William Barron and Mary Ross or Barron. These should tell you the names of their parents including their mothers' maiden names.
You should also plan to view the original baptism records, which may contain additional information, for example names of witnesses, and the original censuses. Also get a copy of what the Parochial Board records say - these can be extremely informative.