1861 Census: Kirktown, Muckairn, Argyll
Alexander McIntyre, 50, wood cutter
Sarah McIntyre, 39
Colin McIntyre, 11
John McIntyre, 9
Margaret McIntyre, 7
Flora McIntyre, 3
1871 Census: 6 High Street, presumably Oban
Alexander McIntyre, 66, fisherman
Sarah McIntyre, 53
Colin McIntyre, 20 fisherman
Flora McIntyre, 12
1881 Census:
Alexander McIntyre, 74
Colin McIntyre, 28
Flora McIntyre, 22
all born Argyll.
I have not found a Duncan, and I can't find any of them after 1881.