The family residence when Edward was born was the village of Corbally, which is located close to the Sligo/Mayo border and less than 10km (~6 miles) from Ballina. The nearest Presbyterian Meeting House to Corbally that I was able to locate was the one in Ballina listed on Charles Street in Slater's 1870 directory.
There's a partial civil marriage extract for George Thompson and Ann Smyth on FamilySearch in 1869 - would probably be worth ordering a research cert to see the full details, as these could give some useful details - e.g. father's occupations, residence of the bride & groom, occupations and names of witnesses. The marriage extract gives the location as 'Killala', which in this collection could refer to the town or townland of that name or a sub-district. The marriage is listed on the Index under Dromore West , which as far as I can tell only covers parts of Co. Sligo (The town of Killala is in Co. Mayo). The cert should show exactly where the marriage took place.