I looked up the record you mention on the IGI and I see Duncan was from Glenmore. That is a large area and includes Fort Augustus, which is also Fraser land. I dont have any links to that family but they were no doubt from the same general area.
Duncan (1834) notified his father's death in 1868 so he was still in Scotland. My branch of that family is through James's brother William and they hailed from Glenurquhart, halfway along Loch Ness on the north bank.