Christine, there is an earlier post on this family and you can look at it here https://irelandxo.com/ireland/louth/dundalk-louth/message-board/mr-josep...
The marriage in 1874 and subsequent children, there are a lot, see some baptisms and some civil registry which is free here but sign in, you will not get church records suitable here but civil from 1864 for all BMDs. https://www.irishgenealogy.ie/en/
They appear to have a lot of problems putting it mildly, the first child in the workhouse I see was 1889, oddly you mention Clare as I see another William Bolton wife Anne Buglar and he is a shopkeeper and farmer in Clare, he cannot be a brother as he is William and I also see searches for this family on this site.
I cannot see them on the census, I do see a Bolton and Murray family in Dundlak on the census and some of the witnesss at birth were Murray. We don't get into later research where living people might be involved but there is a Louth Genealogy Facebook page if you apply to join and may find someone.There is a Bolton Square here in Drogheda as a matter of interest and here is a site on Louth http://www.jbhall.clahs.ie/
Intersting you think he joined the Army as the Irish War of Independence finished late 1921 so assume the Free State Army at the time, we were then more or less straight into the civil war of 1922 to 1923, There is an army museum may assist.