Casserly/Lafferty family of Lissergool

Hello,

I am trying to gather more information about my grandfather's family.  I also would like to know how I go about finding out if there are living relatives, albeit distant, still in Ireland.  I have enclosed a general history of what I know.  Through the Ireland census, I know my great grandmother lived at 16 and 19 Lissergool in 1911 and 1901 respectively.  Her neigbours were Casserly's.  I am assuming they were family of hers.  I also discovered through my internet search that Marianne's father Michael had two brothers: Patrick and John, as well as, a sister Bridget.  This information is yet to be confirmed.  Also, in the 1890 Return of Judical Rents their is a listing for Martin Lafferty and an Ellen Casserly leasing land from R.P. Worthington in Lissergool.  I have four of the brothers coming to Canada with only one staying.  My research has put me in contact with someone who is related to the wife of one of the Lafferty children, Thomas.  Thomas married an Ann Sharkey of Cloonfad and had two children.  Unfortunately they passed away in 2013.  They were both bachelors. I have GRO records for Catherine/Kate, daughter of Martin and Marianne marrying a Thomas McGarry of Cloonmagunane, father Pat in 1922.  

Here is the family

~~My Grandfather was John Lafferty and was born in Ireland on September 21 1878.  His marriage certificate lists his parents as Martin Lafferty and Mary Casserly.  
 Martin (b. 1830 - d. 1897) and Mary/Marianne (b. 1846 - d.1917) were married 28 February 1869 Castlerea, County Roscommon.  The marriage certificate lists the town for Martin as Arthiane(?) and Martin Lafferty as the father of the groom. Michael Casserly is listed as the father of the bride.

  Info on the rest of the children go as follows:
Peter Lafferty - Birth Date: 6 Dec 1870
Michael Lafferty - Birth Date: 5 Jul 1872

Bridget Lafferty - Birth Date: 23 Feb 1874
Martin Lafferty - Birth Date: 8 Sep 1876

Patrick Lafferty - Birth date: 28 Dec 1880

Thomas Lafferty - Birth date: 30 Oct 1883

Catherine Lafferty - Birth date: 24 Sep 1885
Any help you can provide would be greatly appreciated.

Sincerely,

Laurie