did you get an answer?
www.census.nationalarchives.ie 1901/1911
www.familysearch.org for civil birth records from 1864-1940's
www.rootsireland.ie for North or South Dublin Parish records
www.irishgenealogy.ie for Dublin City
www.askaboutireland.ie Griffith Valuation 1846-1862 depending on county
There is 1 Smullen in the current telephone book for Leitrim.
Annette Code