I have McNicholas relatives from Killedan parish as well (that's the parish where Kiltimagh is located), and I had a similar experience when going into a pub in Kiltimagh in the late 1970's for directions. I met very friendly people who knew where my Gallagher/King grandparents had lived, and gave me directions to their townland (Carrownteeaun or Carrantiane), and there I met a first cousin of my mother. There were a number of McNicholas's in that townland, and also just across the parish boundary in Bohola parish, and the Gallagher's and McNicholas's have intermarried for several generations, maybe much longer (I've located more than a dozen Gallagher-McNicholas marriages from the 1820's to the 1870's). I've done DNA testing, by the way, and so have several Gallagher second cousins of mine, in case you're interested in comparing results.
Killedan and Bohola both border the parish of Swin(e)ford. The town of Swinford is the administratve center for the area, so in later civil records you will often see people recited as being born or married there, when they actually lived in another parish. The parish registers in Swinford also go further back than those in Bohola and Killedan, and people from neighboring parishes were sometimes baptized or married in Swinford earlier iin the 19th century, because it already had a church. I've found records there for people who I know were actually living in Killedan or Bohola, so you may want to check there.
I've searched the local parish registers (in their online form) pretty thoroughly over time, and I don't recall seeing anyone named Keane or a Kane. There are a number of King's, to whom I am also related, though more of them lived in Kilcolman parish, which is also nearby. According to MacLysaght's "Surnames of Ireland", Kane/Keane (which are interchangeable variants of the same name) comes from the Irish Ó Catháin in Ulster, and can also come come from the Irish Ó Céin in Waterford, but is not originally a Connacht name. However, there were various Ulster families who moved to Connacht at the time of the Plantation of Ulster (such as my McNulty and O'Neill relatives in Mayo), so some Keane's or Kane's may have comme to Mayo back then.
In case you're interested, the surname McNicholas (Mac Niocláis in Irish) was taken as a surname by some members of the Norman Burke (de Burgo) family, which once ruled much of what is now County Mayo. The parish church in Killedan is the Church of the Holy Family in Kiltimagh, and the parish name comes from the Irish Cill Liadáin (“Liadán’s church”). The town of Kiltimagh (older spelling Kiltamagh, and other variants such as the one you mentioned) is Coillte Mach in Irish. The meaning of the name is disputed, with “milking woods” now believed to be most likely, with less likely meanings being “outer woods” or “woods of the plain”, based on the Irish form Coillte Amach, which modern scholars now believe was not the original form of the name.
Hope some of this was of interest!
