As you know the spelling and pronunciation of names in Ireland is not standardised so Crombie and Cromie might be the same family. I can't find any reference to the name Crombie in Loughinisland but there could have been an isolated family difficult to trace. Church records would sort it out. The Cromie family of Loughinisland/Clough were well known. Alexander Cromie was a doctor 1800-1847. Robert Cromie was also an M.D. and his son Thomas as well. Jack Jordan was an M.D. and was the grandson of Robert through Robert's daughter Annie. Annie married Sir John Newell Jordan 1852-1925 a distinguished diplomat. Dr. Robert Cromie is remembered for planting trees around an ancient Danish fort on land where he was a tenant. J.Cromie, Esq. lived at Draper Hill which is halfway between Ballynahinch and Castlewell. He was the owner of a linen mill established here in 1815 and at one time employed 3000 people. Griffith's Valuations for Loughinisland listed Robert Cromie at Clough and Robert Cromie at Knocksticken. The 1886 Directory listed Dr.R.Cromie who had had a local dispensary and Robert and Thonas Cromie in Clough. In 1853 John Cromie donated money to the Drumaroad R.C. church suggesting thst was the family's religion. In 1882 Thomas Cromie was listed in the Medical Registry of Ireland. In 1885 Thomas Cromie received his degree in Obstetrics from the Royal University of Ireland. No Cromies I found were associated with Drumanigan casting doubt as to whether it was the same family. I think Church and gravestone records would help sort it out. MacLysaght in his, "Surnames of Ireland" lists Cromie and Crombie together saying it is peculiar to South Down and Co. Armagh. Cromie is a Scottish toponymic but families called O'Cromy were in Co. Armagh in the 17th.C so the Irish form O'Cromtha (crom, bent or crooked) can also be accepted. There is a possibility that the Loughinisland Cromies and Crombies were from the same origin though not directly connected.