Although this is rather early for Irish records there maybe some parish records.
There is no county Connaught, it is the name of one of the provinces that Ireland was divided into before the Normans/English invaded and there were still Irish Kings. see
www.from-ireland.net for the history of land divisions in Ireland. Connaught Consists of Galway, Leitrim, Mayo, Roscommon, Sligo
Killian/Killyan in Galway, (Connaught Province).
www.libraryireland.comBallina appears as both a Parish and a townland in Mayo as well as a townland in several other counties including Galway in the Parish of Killeerin, Poor Law Union Tuam.Also a townland in the Parish of Kilmoremoy as well as the Poor Law Union. A PLU town would be where administration would take place for all villages, towns, townlands and the Workhouse would be located all would be within a 12 mi area.
By the time the Griffith Valuation took place 1856 in Galway and there were no Scott's specifically in those parishes. See below.
I did find a Killina in Monaghan County.
The Tithe Applotments are the earliest census substitute 1823-1837
www.genealogy.nationalarchives.ieSome Scott's (7) but no Luke
Griffith Valuation:
www.askaboutireland.ieJohn Scott, Parish of Taghboy, Townland Caltraghduff, Poor Law Union Mountbellew,
tenant of Richard D. Kelly (note Barony of Killian)
#6 house, outbuilding and land 24 acres 2 roods 7 perches
Laurence Scott, Parish Killeroran, Townland Cornanantamore, PLU Mountbellow
tenant of James Thorngate
#9 house, outbuilding and land 4.0.25
Luke probably married about 1803 and you might find the children' births on
www.rootsireland.ie and birth record would give mother's maiden ame.
Try for Matthew or Robert as John would too common a name. Once you have the mother's maiden name you can then search for all children born in Ireland to this couple.
www.igp-web.com can be a good resource depending on which county
Annette Code