Alison,
I have a suggestion about church records. There are 2 other Church of Ireland churches in Clones parish. Aghadrumsee is a couple of miles west of Roslea and Clogh is a mile or two south. Aghadrumsee has baptism, marriage & burial records from 1821 and Clogh from 1811. Copies of both are held in PRONI. My guide to church records indicates Aghadrumsee’s are not on-line anywhere. It doesn’t list Clogh so I can’t advise if they may be on-line. But if the family aren’t showing up in the main Clones parish records then perhaps they used one or other of the other 2 churches, whose records were kept separately.
You can see the churches exact locations using the maps on the Church of Ireland website:
https://www.ireland.anglican.org/find-a-church
The tithes were primarily a tax on land and were paid to the church, so the records were compiled parish by parish, as that suited the church authorities best. Where a parish was in more than one county (which happened regularly) it was normal to lump them all together. Since most of Clones parish is in Co. Monaghan, the records appear in various sites as all under Co. Monaghan, but that’s not accurate. Some actually relate to Fermanagh.
Partition of Ireland in 1922 did not affect the border between Fermanagh & Monaghan. It wasn’t re-drawn, and no townlands have been moved. Likewise the boundaries of the parish of Clones today are still the same, and clergy work in both parts just as pre 1922. In Fermanagh a service will usually include a prayer for the Queen and in Monaghan a prayer for the President of Ireland, but otherwise the parish continues as a single unit.
If you want to see which county a particular townland is actually in, you might find this site helpful. If you put in the parish of Clones (and leave everything else blank) it will show you all the townlands in the whole parish, ie both counties. If you then enter Fermanagh it will filter out those in Monaghan (or vice versa obviously).
https://thecore.com/seanruad/
Regarding spelling, the Seanruad site lists what might be described as a modern standardized version but in the past there was no such thing. The idea of a single or correct spelling for a surname or a place name in Ireland is very much a recent phenomenon designed to meet the needs of modern officialdom. Before that there was no consistency. Names were spelled phonetically and each variation was down to the whim of the particular person recording the information. You will often see the spelling change as the records go back. This rarely indicates a deliberate decision to alter the name, nor even a mistake. Not everyone was literate, but even when they were, exact and consistent spelling simply wasn’t something they bothered about.
In 1899, the Rev Smith reviewed the early records of Antrim 1st Presbyterian church (covering the years 1674 to c 1736). He noted: “Even the same word is not always spelled alike by the same hand. Indeed spelling with most of the recording officials (and they must have been fairly numerous) was a matter of the most sublime indifference. The name William, for instance, is spelled 3 different ways in as many lines; while Donegore, a neighbouring parish, is spelled 10 different ways; but these extend over a good number of years. Many families names are spelled phonetically, while others are given in the most round-about fashion.”
So expect spelling to vary. That was the norm.