I don't think we can answer any of our questions until we search the death, marriage and baptismal records in Toronto for data on the offspring of Thomas Culliton and Johanna Crane and those for the offspring of John Walsh (family emigrated to Chicago before 1880) and James Walsh (still in Toronto in 1881). Thomas and Johanna emigrated to Toronto between 1849 and 1855.
You can find what appears to be your ancestor Christopher Walsh in the 1881 census for St. Patrick's Ward Toronto. This census is available on-line at
www.familysearch.org. Christopher was living with the James Walsh family.
I still doubt that Elizabeth Walsh, age 7 in 1881 Toronto census, was the Elizabeth Walsh who married American John Ryan before 1890, but it is possible. It just raises more questions as to how and when she emigrated to Chicago to meet and marry John Ryan.
Ellen