I have looked on the census for Alexander Gray and Margaret and family and I think I have found them. My only concern is that their DOB seem to get progressively later and then finally down again! In all the census Alexander is listed as born in Insch and Margaret as born in Oyne. From your research they were born in 1830 and 1833 respectively. However in 1861 (Parish: Keig, ED:1, Line 25) their birth years are abt. 1833 and 1835 respectively. In 1871 (where George the next in my lines of descedants is mentioned), (Parish: Tullynestle and Forbes, ED:3, Line 18) their birth years are abt 1835 and 1837 respectively. In 1881 (Parish: Tullynessle anf Forbes, ED:2, Line 7) their birth years are both abt 1836) and in 1891 (Parish Tullynessle and Forbes, ED:2, Line 9) they go back down to 1831 and 1833 respectively!
Do you think they were not truthfull in the middle or have I somehow come across another Alexander Gray and Margret from Insch and Oyne respectively?