Hi all, I have a ubiquitous dead end in my research. I'm hoping someone out there might have some tips on where I should go next on the research front, or better yet weigh in with that all-too-scarse genealogical lynchpin that unlocks the family tree! Regrettably, I have not been able to find the necessary birth, death and marriage certificates for the children that may shed further info on their parents details)

I've got thus far:

John Ogilvie (b?; d c1841) m Isobelli Murdoch (b c1791; d c1841)

Their children:
Elizabeth (b Kingussie 1808 - d Toronto 1875)
Mary (b Kingussie 1809 - d Glasgow 1848)
John (b Aberdeen 1811 - d Sierra Leone 1837)
Alexander (b 1813 Peterhead - d Toronto 1847)
James (b 1814 St Fergus - d 1875 Glasgow)
Jean (b 1816 St Fergus - d 1819 Scotland)
George (b 1818 Fraserburgh - d 1822 Tarrar)
Isabella (b 1820 Hill of Udny - d 1913 Orillia)
Jane (b 1823 Tarrar - d 1898 Ontario)
Robert (b 1827 Rothesay - d 1899 Foxboro)
William (b 1830 Rothesay - d 1890 Greymouth NZ)
Barbara (b 1833 Rothesay - d 1899 Orillia).