Have you tried for gravestones?I have John's birth but not Ann's, but I'm doubtful of getting their deaths. In researching the Parish of Drumoak in "The Statistical Accounts of Scotland", I found the statement that the parish had never kept death records, so if that was the case elsewhere .....
I checked the Aberdeen Family history site http://www.anesfhs.org.uk/ and they have a searchable database for MI's .
There are 11 John Skinners:
booklet: Kirkyard of Banchory-Ternan (AA107)
burial ground: Banchory-Ternan
stone: 128
Catherine Skinner 1852
Isabella Skinner 1861
William Skinner 1873
John Skinner 14 Jan.1888
Christina Ingram 25 Mar. 1899
stone: 237
Robert Skinner 17 Oct.1859
William Skinner 16 Jan.1878
Harvey Skinner 9 Feb.1884
Joseph Skinner 1 Oct.1885
Jane Fraser 17 Dec.1887
John Skinner 25 Mar.1888
Confusingly both of those died in the same year!
The other entries are from the graveyards at: Macduff, Drumblade, Kinnedder, Skene, Leslie, Tarves and Udney.
There are no other details, they will be found in the books - perhaps somebody has a copy or could look it up for you in a library?
2 Anne Ross in the same place:
booklet: Kirkyard of Banchory-Ternan (AA107)
burial ground: Banchory-Ternan
stone: 245
Robert Adams 27 Sept.1890
Ann Ross 26 Apr.1910
stone: 451
George Masson 25 June 1892
John Masson 2 Jan.1896
William Masson 9 Aug.1909
Ann Ross 23 May 1913
James Masson 15 June 1929
but they seem far to young to be of interest.
Not everyone of course had a gravestone, and not all stones have survived or can be read now but it's always worth a shot.