By the 1901 UK census all my G/Quinan/e ancestors had become Gannons in Liverpool.
There are transcripts of the letters that got me on the right track at this link:http://www.ballaratgenealogy.org.au/art/guinane.htm
Reading the letters gives a good run down of all I know about my line.
my biggest mystery is what became of James Guinane's daughter.
If you have any questions about the letters, post here rather than direct so that everyone can see the thread.
Margaret in the Hudson Valley