You could try writing to the 8 Bolton's in the Clare telephone book. There are 80 some Hogan's and unless you can locate them by address I don't know how you would be able to figure out what family is what family.
A child born 1881 would be 30 in 1911 so possibly could be in the 1911 census but there are too many even in Parish Killokennedy.
Normally I would try and figure out who was who but there is a lot of them as all the boys names are so common. The women would be married and difficult to trace.www.familysearch.org
could be helpful look for Limerick Civil Registration for the Parish Killokennedy. I think you would find this difficult because of so many surnames and first names.
Griffith Valuation www.askaboutireland.ie
The name Killokennedy is both a Parish and a townland in the Poor Law Union of Limerick.
Griffith Valuation 1855 has 8 Bolton's and 282 Hogan's
I couldn't locate the name Blackhill except as a townland
in Carlow, Fermanagh, Kildare & Wicklow
Blackhills was in Queen's County Laois, Poor Law Union of
There are two John Bolton's in Griffiths 1855, one in
Parish Kilnoe, Townland Ballydonaghan PLU Scarrif and
Parish Tulla, Townland Tome PLU Tulla
So Parish Killokennedy must of been the Hogan's home parish.
There are 20 Hogan's in the Parish of Killokenndy, 9 of whom are called John. Usually first son given name of father or grandfather.
Co. Clare is one of 4 parish's that don't have Parish records with an Irish History Foundation, this is a pay website.
I understand the Library in Clare has parish records.
There is a genealogical society which only does commission work.
Someone who is more knowledgeable about Clare you probably know where Blackhill, Co. Clare is located.