I really enjoyed reading your letter. I tried to find records related to the Collins family with no success. The townland mentioned by Canon Bourke is Eskerlevally. He mentions within a mile from Claremorris. That may be as the crow flys. Driving it is about 2 miles or so to the north of Claremorris.
I checked the Tithes, Griffiths Valuation and the 1901 census. Also, checked Roots Ireland, again with no success. I'm guessing that Darby and Bridget were married 1827 or earlier and the children in that same time period.
The son Michael likely went to England permanently or died before the 1901 census since there were no Collins living in Eskerlevally.
As an aside, Canon Bourke was famous in his own right, See this article.