Hi Marcii,
This is what I know:
John Cronin born 1819 married Nora (maiden name unknown) born 1841 died 1902
I don't know how many children they had, but here are the ones I know:
1. Michael Cronin b. 1876 married Julia (Walsh) in 1903
2. Nora Cronin b. 1871 possible children are James and Hannah (you're saying this Hannah married James Fitzgerald in 1918) Nora is living with her parents in 1901 but in 1911 she is not.. She could have died or got married. But in 1911 census there is a Nora Cronin living in a workhouse in Lismore
Hannah Cronin age 4 in 1901 is living with her grandfather. She moved in with her Uncle Michael either when he got married in 1903 or when her grandfather died as he is not alive in 1911 census.