Robert was a carpenter who was living in Chateaugay, New York with Hattie and his baby son Walter at the time of the 1870 census.
17 year old Alfred Whipple was living with them - perhaps Hattie's brother?.
Hattie died young and is buried in Earlville cemetery in Chateaugay, New York.

After his wife died, Robert returned to Canada and he remarried in 1876. He died a few months later and is buried in Hillside cemetery.

Martha married George (Henry) Broder (1846-?) in 1879. She is buried in the Franklin Center cemetery.

Walter was raised in Canada by Robert's sister Jane Rennie (1838-1903).

* There was supposed to be a daughter Emma who was raised by Harriet's parents in New York State. I cannot find any record of her.
Emma is not listed on the 1870 census with her parents and she is not on the 1880 census with Harriet's parents Daniel and Agnes.