Hello Sue,
I have little local knowledge just paperwork and census for the area.
The 1841 census shows John 35 and Ann 30 living with family at Glenshone also there was William 35 and Ann 35 (Brew) and their family. Up the road at Ballig was Daniel 35 and Catherine 20 (Kerruish ?) with their children. The male names and ages coincide with some of the children of William Kermeen and Margaret Joughen.
As for John's wife Ann the age shown is 30 but the only Ann Kermeen near was born 1806 and she appears at Ballacorteen, daughter of William Kermeen and Margaret Davies and still single. A guess would suggest that IGI got it wrong and her surname was not Kermeen.
As you will know John Kermeen and Isabel Callow had 3 daughters Isabel ch 1753 Jane ch 1758 and Mary ch 1762. I notice a Jane Kermeen married a John Kermeen at about the right age so it may be worth checking but who the others married would be guesswork for me.

Len Faragher