A parent search on www.familysearch.org
for David Swankie and Isabella Cargill turns up 7 children, all born in St Vigeans between 1861 and 1873. Daniel would be too young to be listed as the FamilySearch listing only goes to 1874. David and Isabella were married in St Vigeans on 11 October 1861.
Go to www.scotlandspeople.gov.uk
and invest in a few credits at modest cost. Use 6 of them to find and download the marriage certificate of David and Isabella. It will tell you the full names of both sets of parents, including their mothers' maiden names. You can use another six to find the marriage of William McConnell and Marion Stobo. You'll still have enough to look at three more certificates or census returns if you get your search right.