Hello Jeff (and Claire), I've read your posts regarding John McGregor, his daughter Ann etc. with interest after finding them in the 1861 census and his complicated family relationships.
I wonder but can't prove if that Ann in 1861 is the same Ann McGregor in this 1841 census entry in Cromdale pasted below.I am pretty sure that Katherine is the mother of both Ann and Janet, who was described as the natural daughter of John MacGregor, farmer in Doune on her marriage record.In census' Janet listed her birthplace as Duthill and Catherine Cumming and John McGregor were listed as her married parents on her death record but I think that was posthumous legitimacy.
Katherine Cumming, 60, b. abt 1781, b. not in Inverness, Ind. Fredrick Fraser, 25 b. abt 1816 born: InvernesshireLodger Janet Fraser, 20, b. abt 1821, b. Invernesshire Lodger Ann McGregor, 25, b. abt 1816, b. Invernesshire, Female Servant