I have done a little more research on your McPherson family. Alexander McPherson was twice married, 1) 14 Jun 1817, Forgue, Aberdeenshire, Margaret Simpson. They had 8 children:
Janet 1816
Margaret 1819, Huntly, Aberdeenshire
Isobel 1822, Forgue, Aberdeenshire
The remaining 5 were all born at Inverkeithny, Banffshire:
Jane 1824
Alexander 1826
Mary 1827
James 1829(died 27 Mar 1880, Wentworth, Ontario aged 51)
Francis 1830
I could not find where Alexander's second marriage took place but it was to Janet Barnet (b. circa 1813 Drumblade, Aberdeenshire). They went on to have 4 children all born at Inverkeithny:
Jessie/Janet 1834
Ann 1839
Helen 1841
John 1843
Alexander (Snr) died at Inverkeithny in 1870 aged 78. He would have actually been 74 as he was born 8 Apr 1796 at Huntly.
James (1829) married Agnes Taylor at Inverkeithny on 16 Dec 1848 and they had 10 of a family:
James 1849 Fordyce, Banffshire
Alexander 1851 Rothiemay, Banffshire
Agnes 1855 (Ontario ?)
Frank 1857 Ontario
Elizabeth 1860
Margaret 1863
William 1866
Robert 1869
Thomas 1870
Isabella 1871
The parents of Alexander (1796) were John McPherson and Margaret Young who married at Huntly, Aberdeenshire on 7 Oct 1788. John's parents may have been William McPherson and Jean Wilson, with a son John having been born at Cairnie, by Huntly on 29 Mar 1763.
I hope that you are able to assimilate all this, and I wish you good luck with your research.