Celbridge town is located within two civil parishes: Donaghcumper and Kildrought. (Straffan is just to the southwest). I looked at the 1852 Griffiths valuation head of household listings for McCanns. There were no McCanns in Straffan and Donaghcumper but two (Abraham and Peter) in Kildrought.
Here is some general info on Celbridge http://en.wikipedia.org/wiki/Celbridge
Here is a link to the RC parish http://www.celstra.ie/our-parish in case you want to contact them for information.
The 1901 census shows an unmarried James McCann living in Oldtown. Not sure if this is the James mentioned in your note. There was also a Kate McCann in Parsonstown.