I don’t know if you have tried
www.familysearch.com. I reduced the list to those born pre 1800, and then changed my mind as some marriages listed
1. John Cooper - International Genealogical Index
Gender: Male Birth: About 1797 Ballyminstra,Killinchy, , Down, Ireland
2. JOHN COOPER - International Genealogical Index
Gender: Male Birth: 1831 Of, Comber, Down, Ireland
3. John Cooper - International Genealogical Index
Gender: Male Birth: , Down, Ireland
4. John Cooper - International Genealogical Index
Gender: Male Birth: About 1796 Killinchy, , Down, Ireland
5. John COOPER - International Genealogical Index
Gender: Male Birth: About 1815 , Down, Ireland
6. JOHN COOPER - International Genealogical Index
Gender: Male Birth: 1817 Ards, , Down, Ireland
7. John Cooper - International Genealogical Index
Gender: Male Birth: About 1814 , Down, Ireland
8. John Cooper - International Genealogical Index
Gender: Male Birth: About 1834 Magherabeg,Dromore, , Down, Ireland
9. JOHN COOPER - International Genealogical Index
Gender: Male Birth: 23 MAY 1865 0527, Strangford, Down, Ireland
10. JOHN COOPER - International Genealogical Index
Gender: Male Christening: 01 JAN 1787 Knockbreda, Down, Ireland
11. JOHN COOPER - International Genealogical Index
Gender: Male Birth: 1829 , Down, Ireland
12. John Cooper - International Genealogical Index
Gender: Male Birth: 15 SEP 1879 Castleuagh, , Down, Ireland
13. JOHN COOPER - International Genealogical Index
Gender: Male Birth: 1831 Of, Comber, Down, Ireland
14. John Hugh Cooper - International Genealogical Index
Gender: Male Birth: 15 MAY 1877 Banbridge, Down, Ireland
15. John Cooper - International Genealogical Index
Gender: Male Birth: 14 FEB 1879 , Down, Ireland
16. John Croskerg Cooper - International Genealogical Index
Gender: Male Birth: 22 DEC 1878 , Down, Ireland
17. JOHN COOPER - International Genealogical Index
Gender: Male Birth: 25 OCT 1867 , Down, Ireland
18. John Cooper - International Genealogical Index
Gender: Male Birth: About 1803 Ballow,Killinchy, , Down, Ireland
19. Mrs John Cooper - International Genealogical Index
Gender: Female Birth: About 1808 Killinchy, , Down, Ireland
20. John H. Cooper - International Genealogical Index
Gender: Male Burial: Whitechurch Graveyard,Ballywalter, , Down, Ireland
21. JOHN COOPER - International Genealogical Index
Gender: Male Death: 1881
22. JOHN COOPER - International Genealogical Index
Gender: Male Death: 1881
23. JOHN COOPER - International Genealogical Index
Gender: Male Death: 16 FEB 1897
24. John H. Cooper - International Genealogical Index
Gender: Male Burial: Whitechurch Graveyard,Ballywalter, , Down, Ireland
25. John Cooper - International Genealogical Index
Gender: Male Marriage: 14 AUG 1777 Donaghadee, Down, Ireland
26. John Cooper - International Genealogical Index
Gender: Male Marriage: 09 MAR 1840 Donaghadee, Down, Ireland
27. JOHN COOPER - International Genealogical Index
Gender: Male Marriage: 1834 Of, , Down, Ireland
28. John COOPER - International Genealogical Index
Gender: Male Marriage: About 1841 , Down, Ireland
29. John Cooper - International Genealogical Index
Gender: Male Marriage: About 1859 Dromore, , Down, Ireland
30. John Cooper - International Genealogical Index
Gender: Male Marriage: 1844 , Down, Ireland
31. JOHN COOPER - International Genealogical Index
Gender: Male Marriage: 04 JAN 1822 Presbyterian,Killinchy, , Down, Ireland
32. JOHN COOPER - International Genealogical Index
Gender: Male Marriage: 05 OCT 1822 Presbyterian,Killinchy, , Down, Ireland
33. JOHN COOPER - International Genealogical Index
Gender: Male Marriage: 23 DEC 1833 Presbyterian, Kilmore Parish, Down, Ireland
34. JOHN COOPER - International Genealogical Index
Gender: Male Marriage: 13 OCT 1748 Comber, Down, Ireland
35. JOHN COOPER - International Genealogical Index
Gender: Male Marriage: 24 OCT 1854 Newtown-Ardes, Down, Ireland
36. John Cooper - International Genealogical Index
Gender: Male Marriage: About 1829 Killinchy, , Down, Ireland
37. Mrs John Cooper - International Genealogical Index
Gender: Female Marriage: About 1829 Killinchy, , Down, Ireland
Whitechurch Graveyard,Ballywalter has has its tombstones photographed by ? Bill Cardwell from memory and these are on line. Two of the marraiages have a J as second name eg Maria J and Sarah J both of which are often Jane. So do you think the line connects to any of the above. He was very elderly when moving ? Good luck, Jim