The 1841 census shows their first two children, Henry and James, born Scotland.
Andrew, Jane and Elizabeth born in Ramsey.

The family are in the 1851 census for Ramsey.

1841, Ramsey, district 2, page 6, College Street
James cumming, 30, ship carpenter, Scotland
Jane, 25, Scotland
Henry, 9, Scotland
James, 8, Scotland
Andrew, 5, Isle of Man
Jane, 3, Isle of Man
Elizabeth, 1, Isle of Man

1851, Maughold, district 2, schedule 59, Faliew
James Cummins, head, marred, 48, ship carpenter, Scotland
Jane, wife, married, 45, Scotland
Henrietta, daughter, unmarried, 19, at home, Scotland
James, son, unmarried, 17, at home, scotland
Andrew, son, unmarried, 15, at home, Ramsey
Jane, daughter, 13, Ramsey
Edith, daughter, 11, Ramsey

I have confirmed the names Henry & Henrietta. They may be the same person with the possibility of an enumerators copying error in 1841.