It looks like no connection between our family, but it would be nice to correct & add to my previous posting & then stop cluttering the Newfoundland forum because events move over to Cape Breton. Hope you don't mind this being in your thread.
Some new information found by third cousins, also descendant of the Ellen Walsh born 1819 in Ireland:
It looks like the family emmigrated from Ireland in late 1850, because there was a land sale from John and Ellen Walsh (this is likely the Ellen Walsh b. 1786 in Newfoundland) to Timothy and Ellen (Walsh) Hennessey . This takes place, however, in Little Bras d'Or, Cape Breton at the time.
The mystery is how did Ellen unknown of Newfoundland reach Cape Breton (not difficult, but the circumstances remain a mystery) & marry John Walsh. They are owning land in Little Bras d'Or & sell to a couple, just come from Ireland at a nominal price indicative of a sale between family members, but who are indicated in all later records, like the census entry above & marriage records, to be their daughter and her husband.
It may be that John Walsh and Ellen married in Newfoundland but that John is a much older sibling or uncle tothe Ellen Walsh born 1819 in Ireland. Then they all settle in Cape Breton, unaware of how puzzled their descendants will be.