I'm from the same Meenies / Drimoleague Kingston branch; my grandfather was Richard Kingston (born 23 Sep 1876), younger brother of your William (who I have listed as moving to Oakham in England). I remember their younger sister Susan- she ended up in Engalnd working as a health visitor.
I have a family tree which gives their father and mother as William Kingston (born 1835, baptized 15 March 1835) and Anne Deane.
William's father was Samuel, born 1803 and married to Mary Kingston; and Samuel's parents were George (born about 1770) and Mary. Nothing before that.