Isaac born 1897/98 is unlikely to be Nicholas' son, some 30 years after the marriage of the parents.
Freeholder Records show a Nicholas McCann in 1830 in Ballyhanon (sic), Co. Armagh. There is also a Henry McCann noted in the same place at the same time.
This might be Nicholas Sr's death:
Name: Nicholas McCann 
Estimated birth year: abt 1795 
Date of Registration: 1869 
Death Age: 74 
Registration district: Lurgan 
Volume: 6 
Page: 571 
FHL Film Number: 101584 
Griffiths Valuation (taken about 1864 in Co. Armagh) show the two possibilities (likely father and son):
Occupier: Nicholas M'Cann 
Lessor: Stewart Blacker 
County: Armagh 
Barony: Oneilland, East 
Parish: Seagoe 
Townland: Ballyhannon 
OS Page Numbers: 10 
Occupier: Nicholas M'Cann 
Lessor: Anne Jennett 
County: Armagh 
Barony: Oneilland, East 
Parish: Seagoe 
Townland: Breagh 
OS Page Numbers: 10 
Also a sublet of note:
Occupier: John M'Cann 
Lessor: Nicholas M'Cann 
County: Armagh 
Barony: Oneilland, East 
Parish: Seagoe 
Townland: Ballyhannon 
OS Page Numbers: 10 
Henry also appears in the Revision Books when his land was taken over by Simon Somerville in the first revision in 1875.  There are numerous revisions to the McCann properties in Ballyhannon that are too difficult to list here, so suggest you have a look for yourself at the PRONI website.