Hi Jennifer,
I had a look for the Conneelys on a variety of sites: Griffiths Valuation, Tithe Applotments, Irish Censuses & found a few.
The 1901 Census (free at census.nationalarchives.ie/) has 12 Conneelys in Ervallagh
www.rootsireland.ie/ (subscription site) has 49 Conneely baptisms 1870 + - 10 years in Roundstone R C parish with 19 in Innishlacken so your man was correct.
I'll let you sort them into families - dates are baptisms:
Patrick 19/8/1872 Patrick Conneely & Mary McDonagh
Bridget 26/12/1873 Coleman C & Mary Woods
Bridget 9/1/1875 Michael C & Margaret O'Toole
Festus 16/1/1873 Thomas C 7 Mary Gorham
John 15/5/1875 Joseph C & Julia King
Bridget 1/2/1876 Thomas & Mary Gorham
Bridget 5/5/1877 Patrick & Ann Conneely?
Joseph 14/10/1877 Joseph & Julia King
Mary 12/2/1877 Coleman & mary Woods
Mary 20/1/1877 Michael & Margaret Toole
Anne 13/10/1878 Coleman & Mary Woods
Anne 24/11/1878 Patrick & Anne ?
Coleman 16/6/1878 Michael & Margaret
Michael 18/8/1878 Patrick & Anne Mannion
Bridget 24/12/1879 Patrick & Anne mannion
Catherine 14/12/1879 Thomas & Mary Gorham
Margaret 12/9/1880 Patrick & Anne ?
Patrick 11/1/1890 Joseph & Julia King
There were none in Roundstone C of I parish
There are 22 Conneely marriages 1870 + - 10 years 9 of which mention Inishlacken as bride's address.
I searched without the years specified and got more later marriages - up to 1900 & found another 6 from Inishlacken; I did the same for baptisms and got another 84 but I didn't go through those for inislacken yet.
I'm happy to look for your Conneelys further if you post who you're looking for
Col