The 1901 Irish census notes that Margaret Quinn was married. Are you sure the James who died in 1900 was the correct one?

Also, note that there was a son James in the 1901 census. He was likely a child of James Quinn and his first wife.

 

Residents of a house 23 in Ballynahow (Ballycahill, Tipperary)

 

SurnameForenameAgeSexRelation to headReligionBirthplaceOccupationLiteracyIrish LanguageMarital StatusSpecified Illnesses

QuinnMargaret40FemaleHead of FamilyRoman CatholicCo TipperaryFarmerRead-Married-

QuinnJames16MaleSonRoman CatholicCo TipperaryScholarRead and write-Not Married-

QuinnWinifred7FemaleDaughterRoman CatholicCo Tipperary-Cannot read-Not Married-

QuinnMargaret7FemaleDaughterRoman CatholicCo Tipperary-Cannot read-Not Married-

Thank you for the spelling of Mullaunbrack and the clarification of where it is located in relation to Thurles. 

The death record was the only one I could find for a William Quinn in the area close to that time. His daughter Margarete told her family he had died when she was about 4 or 5.

The 1901 Census is confusing - son James is from Margaret's first marriage to Edmund Morrissey. Maybe a neighbor gave the information or one of his little sisters and the enumerator assumed he was a Quinn. On their immigration record in 1907 his last name is listed as Quinn as well but going forward all records list him as Morrissey. 

It does say Margaret is married in 1901 - I haven't been able to locate a William Quinn of the right age living alone who is married - so again maybe a neighbor gave the info? 

Thank you for all your assistance!