Drennans in Borris in Ossory and Knockaroo / Aghaboe

My grandfather William Drennan was Born 7 Nov 1887 in Borris in Ossory and registered on 5 Dec 1887 [Birth Cert available] and registered in Roscrea. His siblings were all born ranging from years 1873 to 1890 in Borris in Ossory.
My great grandfather William Drennan [as best as I can find out at the moment] was born 9 Aug 1834 in Ballykevin/Barna, near Knockaroo, Aghaboe Parish on 9 Aug 1934. His siblings were born ranging from 1839 1839 an same location. [from Aghaboe parish records]
Their parents were Michael and Elizabeth [Short] Drennan.

I know that my grandfather and great-grandfather and family moved into a house [I visited them in the house] close to Borris in Ossory on the Roscrea road in 1894 [from cancellation books in the valuation office] and the 1901 & 1911 Census. The house is still there. I am told that they were evicted in the 1880s from a small holding in Knockaroo.
I am trying to locate where they were Between 1839 and 1894.
Also if there could be any other records showing details of Michael drennan ans Elizabeth Short.
Can you advise please where I could go to get more information. I have been in contact with the library in Tullamore where there are allot of Laois church records. I was hoping there might be local libraries or museums etc. I did visit Donnaghmore workhouse shortly after it became a museum but there was very little info there at that time.
I am available to travel there at any time.
Regards

Larry Drennan
____________________________
Tel: +353-1-8259395
Mobile: +353-86-8392062
Email: drennan380@gmail.com