I see that in 1861 Duncan was aged 26, an iron ship builder, born Burnparish (I assume Barony). I also see from the GRO index that the children were Salena Catherine 1857, Sarah 1859, Abel 1861, Duncan 1864, Daniel 1867, Rebecca 1869, Emma 1873, and Agnes 1878. No Hugh, so they were obviously not following the Scottish naming tradition.
In the 1881 census there is also a 4-year-old daughter Jane, but the only birth of a Jane McGregor in Sunderland in 1875-1877 is to a mother with surname Hunt. I note with passing interest that in 1871 Duncan's household includes William Hunt, 19, brother and Emma, 15, Martha, 14 and Eliza, 12, Hunt, sisters, all born Hartlepool.