Hello and Welcome to Ireland Reaching Out.
Have you any dates for Sarah Cody and John Delaney
This is the link to the Parish Records for Rahan and Lynally, marriage records start in 1810, now there are some missing years.
https://registers.nli.ie/parishes/0956 - Rahan
https://registers.nli.ie/parishes/0933 - Tullamore
Now you may need to search Tullamore records as Charleville is on the Tullamore end of the Parish. It depends where Sarah came from Rahan or Tullamore, as people usually married in the brides Parish.
Also have you done your DNA, it might help with finding relatives still in the area.
Geraldine