I have some new information on Williams Wilsons sister, I found through chatting with an ancestry DNA match:
Williams details again for ref:
William Wilson Marriage 1869In Culfeightrin, County Antrim, Northern Ireland on 26 Jan 1869
William Wilson Age: Full (Residence: Ballreagh, Culfeightrin) Occupation: Miner
Martha Welsh Age: 18 (Residence: Drumnakeel, Culfeightrin)
Wiliams Father: John Wilson (Occupation: Miller)
Witnesses: Hugh Welsh & Fanny Jane Welsh
https://civilrecords.irishgenealogy.ie/churchrecords/images/marriage_returns/marriages_1869/11407/8188729.pdfWilliams Wilsons Sister:Mary Jane Wilson Marriage 1871In Ballymoney, County Antrim, Northern Ireland on 24 Jan 1871
Mary Jane Wilson Age: Full (Residence: Devrock, Derrykeighan, Dunluce Lower, Co Antrim)
Patrick McCullagh Age: Full (Residence: Devrock, Derrykeighan, Dunluce Lower, Co Antrim)
Mary Janes Father: John Wilson (Labourer)
Patrick McCullaghs father: Patrick McCullagh (Chimney Sweep)
Witnesses: Robert Steele & Robert

?
https://civilrecords.irishgenealogy.ie/churchrecords/images/marriage_returns/marriages_1870/11367/8173352.pdfMary Jane Wilson Census 1901https://www.census.nationalarchives.ie/pages/1901/Antrim/Bushmills/Bushmills_Town__part_of_/943450/https://www.census.nationalarchives.ie/reels/nai000293334/My match on ancestry mentioned that their linegage goes through their mother to Patrick McCullagh and Annie McGaghey, and through Patrick to his father Patrick McCullagh married to Mary-Jane Wilson. They were based in and around Bushmills, though some of their children might have been born in Coleraine district. Both Patricks were chimney sweeps and their life was tough and improverished.
Mary Jane Wilson was based in Devrock, Derrykeighan, Dunluce Lower, Co Antrim at the time of marriage.
Not sure if these details may help in finding John Wilson and Elizabeth Wylie, but it's good to know he had a sister.