https://www.scotlandspeople.gov.uk for Scottish records, a free to search site, low cost to view records.
I cannot find the marriage of ALLAN MCDOUGALL and MARY MCPHERSON on
SP but I do see the baptism of Margaret in 1791, she appears to be their only child in "Kilmore and Kilbride, a united maritime parish of Lorn, Argyllshire, containing the town of Oban, so I am guessing this is Allan below, not quite Jura though but the only one in 1759?
ALLAN MCDOUGAL 27/06/1759 parents ALLAN MCDOUGAL/KATHRINE MCDOUGALD " Kilmelfort & Kilninver, a hamlet and a parish in Lorn district, Argyllshire. The only other child appears to be MARY 29/01/1761
A MARY MCPHERSON was born the in 1766 but I assume died as the same parents DUGALD MCPHERSON/CATHARINE MCCOLL had a second daughter of that name baptised 4/09/1768.
There was also a MARY MCPHERSON 20/01/1768, parents DONALD MCPHERSON/MARY MCIANLAICH at Kilninian and Kilmore and a number of others elsewhere in Argyllshire.
Most baptism records in the places above start in the 1750s, marriages shortly after but very few deaths recorded until 1855 when statutory registration started.
The Kirk Session records on SP might provide some information, Kilninian and Kilmore records start in 1766.
Colin