I'm not sure about either the George or Janet. I think that G. H. was Gilbert Hunt Todd and Heriot Maggie's mother was Gilbert's second wife Jane.
In 1851 census. Gilbert H. Tod (30, storekeeper, Scotland) (transcribed as Tad) and his wife Margaret (20, Scotland) (transcribed as Ted) were living in Nichol Twp. Wellington Co., Canada West which is where Fergus was located at that time. http://central.bac-lac.gc.ca/.item/?app=Census1851&op=pdf&id=e002372059
Headstone in St. Andrews Auld Presbyterian Kirkyard in Fergus for Margaret, 1st wife of G. H. Todd, died May 13, 1852, aged 21 years. https://www.findagrave.com/memorial/161761190/margaret-todd
In 1861 census. Gilbert Todd (38, clerk, Scotland) and his wife Jane (28, Ireland) were living in the village of Fergus, Wellington Co., Canada West. Children living with them included Elis. (7), Mary (5), William R. (3) and Henrietta (1). https://central.bac-lac.gc.ca/.item/?app=Census1861&op=&img&id=4391573_00570
Avove headstone in St. Andrews Auld Presbyterian Kirkyard in Fergus for Jane, 2nd wife of G. H. Todd, died Aug. 27, 1861, aged 30 years.
In the 1871 census, the widower Gilbert Todd (48, watchman, Scotland) was living in a hotel in Fergus.
Further down on the same page, Henrietta Todd (10) was living with a Henrietta Stuart (30, Ireland). https://central.bac-lac.gc.ca/.item/?app=Census1871&op=&img&id=4396615_00009
William Todd (13) was living in Fergus with the painter Stephen Nelson. https://central.bac-lac.gc.ca/.item/?app=Census1871&op=&img&id=4396615_00009
I believe that Elizabeth Todd was living on Toronto Twp. in 1871 with the family of Joseph and Eliza Forester. (Eliza Forester’s maiden name appears to have been Stewart). https://www.ancestry.ca/discoveryui-content/view/1623660:1578?tid=&pid=&queryId=19b171569c130b74d42d293e4b5ec562&_phsrc=Bvr316&_phstart=successSource
In 1874, Herriot Margaret Todd (18) of Fergus, daughter of G. H. Todd and Jane Stewart, married Udnay Wilson (22) of Elora. One witness was Elizabeth Todd of Toronto Twp. https://www.ancestry.ca/imageviewer/collections/7921/images/ONMS932_15-1354?usePUB=true&_phsrc=Bvr309&_phstart=successSource&usePUBJs=true&pId=81767788
They lived in Shelburne, Grey East Ontario in 1881 but by 1910 were living in Detroit.
Henrietta Todd lived in and married in Detroit in the 1900s.