Hi Roby,
You could order the birth certificates from
www.groireland.ie for the births after 1864
Using this website
http://pilot.familysearch.org/recordsearch/start.html#c=1408347;p=collectionDetailsYou can get the Volume Number and Page number which would be handy for you application
For example
FANNY ELLENOR SYMMONS
Registration District: Dublin South
Year: 1865
Volume 2 Page 783
The form is not designed for this information but include it where you can and don't mention that its from LDS site as they may reject application.
A photocopy of the certificate's would be the best option for research.
The birth certificate would have some additional information such as father's occupation and also an informant of registration which was usually one of the parents but sometimes could be someone else like an aunt uncle etc.
Any other help you need let us know
I not sure if the Baptism recorded originally kept at the church will have more information. The original links i posted are a transcription of the church records but i not sure if there was no witnesses are maybe they did not transcrib them.
Ger