Pete,
I did a little more research before reading your latest posts. I think we agree about everything. I didn't know about the two RC churches in the same parish.
I find the Placenames Database of Ireland at
logainm.ie very useful. If I read it right:
My Fearboy is listed at
http://www.logainm.ie/42129.aspx It's in the barony of Kilcoursey and the civil parish of Kilcumreragh, in Co. Offaly. Its coordinates are N 22715 39286. Your Lurgan or Lorgan is at
http://www.logainm.ie/42073.aspx It's also in Offaly and the barony of Kilcoursey, but its civil parish is Kilmanaghan and it's at N 19898 36033.
Mitchell's
A New Genealogical Atlas of Ireland then confirms your other point, that the RC parish of Tubber spans the Offaly/Westmeath border.
Looking at those great hybrid maps for Griffith's at AskAboutIreland: it appears Fearboy is east of Moate between the R446 and the railway line, while Lurgan is south and slightly east of Moate, south of the M6.
There is a Rosemount northeast of Fearboy in Co. Westmeath, in the opposite direction from Lurgan. Since my church records mention Co. Westmeath, perhaps that's where my grandmother was baptized. That's what you said too: St. Thomas.
By the way, if there was a Stones fortune, I haven't seen it on this side of the Atlantic either.
Mike