Trying to locate John James Mulligan born in Ireland abt 1848

Hello, I am researching my Great Grandfather John James Mulligan, b 2 Feb 1847 in Ireland. His death certificate says he was 60 years old. I would like to know where in Ireland he came from as we are planning a visit for July. I would like to share with you that I have found so far, I hope this helps locate him. His death certificate has his father's name as Martin, mother unattainable He has various birth dates and years His grave marker has his date of birth as 1838 1870 census b as 1848 1880 census b 1847 1900 census b Dec 1848 1910 census b 1850 His first wife is Elizabeth (Bessie) is buried at https://www.stjoenew.com/page/genealogy New St. Joe burials. The record for Elizabeth Mulligan, buried 7 Aug 1871, states that her parents were “Anthony & Elizabeth Hesen”. The indexed information also states that she was from County Mayo and the priest was “Eggelmeers”. There are two records one has her named spelled as Hesen the other as Hazen.  They are attached.I don’t know if he was married in Ireland or New York since their eldest child Mary was Born in New York. It is listed on her death certificate and on census. Her date of birth on her certificate was Sept 29, 1873. I found a record from Find my past of a Mary Ann Mulligan born 18 Sep 1865. She was baptized. 1 Oct 1865 at St Francis Xavier church in Manhattan NY her parents were John Mulligan and Elizabeth Hardin. Also, I have found a John Married to an Elizabeth in Roscommon with a father named Martin a. A civil marriage registration by John Mulligan in 1865 in the registration district of Roscommon Co. Ireland. b. A marriage record for John Mulligan and Elizabeth Curly on 13 FEB 1865. Father's name: Martin Mulligan. Martin was the name listed as father on his death certificate. c. Marriage location: Glinsk, Ireland, Catholic Diocese of Elphin. (FYI: this is the same location where Mary Eagan and John Connelly married) copy of an 1865 Passenger list for John and Mary A. Mulligan. Details: New York, Passenger and Crew Lists (including Castle Garden and Ellis Island), 1820-1957. Film Image #7; dated: June 23, 1865, ship---William Tapscott. Ages on the list seem to match the 1870 US Census. The name of Mary that is listed obviously does not match the first name of an Elizabeth. I truly hope you can help me locate my Mulligan! Janis Howison van Ryswyk