Church of England in Ireland would indeed be Church of Ireland.
Donaghmore Church of Ireland has records from the 1740s, so that looks encouraging. Someone has also obligingly indexed all the marriages for the years 1741 to 1883, and burials 1741 to 1883 are also indexed. According to my guide to Church of Ireland records the originals are held by the church (but there is a fee to view them) and there’s a copy of the records in PRONI (the public record office) in Belfast, which is free to view.
If you can’t get to PRONI yourself you may need employ a researcher.
There was a James Watson farming in Tullylig in 1826, as per the tithe applotment records. Several Stewart households in the parish, including one in Tullylig headed by the widow Stewart. (Perhaps John married the girl next door?). James Stewart was farming plot 11 in Tullylig in Griffiths in 1859, which was just under 20 acres. (Just off the modern Liskittle Rd).
http://www.cotyroneireland.com/tithe/donaghmore.html
Probate abstract from PRONI wills site:
The Will of William Stewart late of Tullylig County Tyrone Farmer deceased who died 25 January 1877 at same place was proved at Armagh by the oath of James Alexander Woods of Drumbearn (Donaghmore) County Tyrone Farmer the sole Executor.
The will itself is on-line and mentions William Stewart’s sister Sarah Anne Woods in Canada as well as William Stewart (relationship not given). William was 70 when he died (according to the GRONI death indexes).
The farm looks to have been sold after William’s death as it’s in James Mckeown’s name by 1879, according to the valuation revision records:
http://apps.proni.gov.uk/Val12B/RelatedVolume.aspx?5402
No Watsons or Stewarts in Tullylig in the 1901 census:
http://www.census.nationalarchives.ie/pages/1901/Tyrone/Stewartstown/Tullylig/
