Brian:
The Roots Ireland transcription records only show Oldcastle parish but I have to believe they were Catholic. When I search for the children in the Oldcastle C of I church, I got no record but when I search under Oldcastle RC church, I get the five children.
Regarding the gap, Ahoghill Antrim provided some good reasons why no records were found between 1832 and 1840. On July 8th, the National Library of Ireland will be placing all RC parish registers online for free searching. I would go through the register and see if you can locate possible faded/illegible records for other children.
I gave you the transcribed Roots records for Michael and John below. Same mother
Roger McDonnell
Church Baptism Record
Name: John Kiernan Date of Birth:
Date of Baptism: 12-Jan-1841
Address: Parish/District: Oldcastle
Gender: County Co. Meath
Denomination:
Father: Michael Kiernan Mother: Bridget Coyle
Occupation:
Sponsor 1 /
Informant 1: Coyle Peter Sponsor 2 /
Informant 2:
Church Baptism Record
Name: Michael Kiernan Date of Birth:
Date of Baptism: 25-Apr-1832
Address: () Parish/District: Oldcastle
Gender: County Co. Meath
Denomination:
Father: Michael Kiernan Mother: Bridget Coyle
Occupation: ()
Sponsor 1 /
Informant 1: Coyle Patrick Sponsor 2 /
Informant 2: Smyth Catherine