I went searching knowing you are stuck so I ignored your work and went looking for Holden and Walsh/Welshby records only in the hope something might click.
Back in 1832, there are 13 Holden listed in Clones civil parish on
http://titheapplotmentbooks.nationalarchives.ie/. There are 55 Walshs in Monaghan but none in Clones parish however it looks like the spelling changed as there are nearly 20 Welshs in Clones in 1832
Back in 1861 in Griffiths valuation {which has updates since} has the following in the civil parish of Clones which I have set out into townlands. It is worth noting that Clones civil parish is split along the border between Monaghan and Fermanagh
Holden William, Jr. Carrivetragh Clones Monaghan gone by 1901
Holden Wm Carrivetragh Clones Monaghan gone by 1901
Holden Joseph Clones Whitehall St Monaghan, gone or Lisoarty in 1901
Holden Mary Coraghy Clones Monaghan
Holden James Coraghy Clones Monaghan gone by 1901
Holden William Coraghy Clones Monaghan gone by 1901
Holden Samuel Drumadrainy Clones Monaghan gone by 1901
Holden Thomas Gortnawinny Clones Monaghan gone by 1901
Also in Clones civil parish are
Walsh John Clones Cara St Clones Monaghan
Walsh Maria Clones Whitehall St Clones Monaghan
Walsh Samuel Clones Fermanagh St Clones Monaghan
Walsh Samuel Clonkeen (Cole) Clones Monaghan
Walsh Maria Legarhill Clones Monaghan
Walsh Rev. Charles Magheranure Clones Monaghan
But no Welsh at all.
From which I determine a Holden and a Walsh family are living in the same street. I also note a clergyman which might strain mixed marriages etc and be a reason to leave a district.
The Irish 1901 census doesn’t use the civil parish but a district. Clones Rural which should mean it also has Clones Urban? Again I have arranged by twonlandsin the same townlands are living
Holden Anne Jane Aghafin Clones Rural Monaghan 68 F
Holden Ellen Coraghy Clones Rural Monaghan 84 F
Holden Mary Coraghy Clones Rural Monaghan 78 F
Holden Florance Lisoarty Clones Rural Monaghan 0 F
Holden Eliza Jane Lisoarty Clones Rural Monaghan 51 F
Holden John Lisoarty Clones Rural Monaghan 80 M
Holden Joseph Lisoarty Clones Rural Monaghan 38 M
Holden Margaret Lisoarty Clones Rural Monaghan 23 F
Holden Sarah Jane Lisoarty Clones Rural Monaghan 3 F
Holden Robert Lisoarty Clones Rural Monaghan 33 M
Holden Minnie Magheranure Clones Rural Monaghan 30 F
Church records for Clones are listed on PRONI see section on Online Quides and select the first item Guide to church records then see page 141. I am stopping here as out of time available.
I would pursue the church records if you haven’t already. I would switch forums to monaghan for this query
Good luck Jim