To fill in details, Valentine and Elizabeth were baptized in 1823 at Seagoe's COI church by John and Margaret of Lisnamintry. Elizabeth was baptized Oct 13, 1827 by the same couple. John Jr. 28, a farmer in Lisnamintry with father John married Sarah Macoun 28, a farmer with father James of Moyraverty July 31, 1851 at Seagoe. There is a death/burial record at Seagoe of Margaret of Lisnimintry June 23, 1865 aged 71. A Lisnamintry Harrison family was listed in Knocknamuckley's 1857 census: John Sr. 70 farmer,. Margaret 61, and Elizabeth 24. The Malcolmson families following the Harrison listing mention that Henry Harrison (no location and there were several people of that name at the church) sired a baby by one of their daughters. A gravestone at Knocknamuckley lists John Harrison of Lisnamintry dying Nov 26, 1885 @71 years and wife Sarah dying Aug 10, 1898 @81 years.
Possibly important are the records of John and Margery of Drumnagoon having Rachel in 1801 and John in 1803 which sounds far too early. Henry Dynes Harrison baptized Nov 21, 1814 and Sarah were baptized on Sept 2, 1816 by a John and Margaret, but no location was given. My Seagoe records omit sections of dates, so there may be more information available at Seagoe. A Sarah was listed in the 1879 Seagoe census as having son Richard Robinson living with her in Lisnisky, A Sarah who might be unmarried died in 1900 @ "69."
John born to weaver James and Margaret was born in Ballyhannon as stated, and Isaiah in Levaghrey. Thomas was born in Edenderry where James was a factory worker per Seagoe records.
Interestingly Pierce and Mary (Sergeant) Harrison married in 1834 (no details) are also in Lisnamintry having Letitia 1835 and William John in 1837. Pierce is living in Moyraverty when Letitia married.
With dates off so much, it is hard to say which facts are related, but perhaps family members can specify more locations and names involved.