Have you checked the Decedents lists on the front of the bundles of wills. These have now also been transcribed by volunteers, but I haven't heard of plans to digitise. They should list adult burials from the parish during the relevant period of the year i.e. the season for Archdeaconry probate or that for episcopal probate. Theoretically, if an adult was buried, but there is no immediate will or admon, there should be a note of the reason - usually 'paup' or 'respited' i.e. they were too poor to bother proving their estate, or proceedings were postponed.

Not sure how well this was all operating at the period you are looking at, but it is worth checking both Arch and Episcopal wills. If you list the burials around the one you have found, you should spot the sequence in the decedents.
Don't forget Douglas events were recorded in Braddan most of the time. One family of Corkill is mentioned in my Vol. I Survey of Douglas 1705, but not fitting immediately with your interests.