JOHN KENNY and MARGARET QUINN of MAYO

my great great grandparents are:
John Kenny, born 1878 and margaret Quinn.
I cannot find him anywhere!!! he lived in Belfast, moved to Clogher, met Margaret and was a Royal Irish Constable. i don't know any children, but Archibald Kenny (my great grampa)
he was friends or related to a Sister Attracta from Birmingham.
i have a letter from John Kenny's niece in Ireland to my gramma McLaughlin in NY that was writtien in 1978 by Shelbie ????? (can't read handwriting)
the letter mentions:
aunt b, briged and patty O ???? (can't read it), aunt marie ann, Mary O Kane and Sean. don't know if all are related, but if anyone recognizes anyone i have mentioned i will be forever grateful.

-peace!!