After a lot more research and the recent possession of a letter written by Elizabeth to James in 1876 I am making great progress.

I now know that Waringstown is the right place. Elizabeth died in 1884 and was taken back to Donaghcloney to be buried.
Still no idea where John Ncholson fits in but sure now that Elizabeth was the housekeeper at Court na Farraga in Killiney.

Thanks to Elwyn for advising me that records are available at PRONI regarding marriages and baptisms at Church of Ireland at Donaghcloney.

So near but so far away!! Can anyone advise me on how I can gain this information. Does the PRONI conduct searches at a cost. Any idea how much they charge to look up info in the same Church record for specified people?