Hi Margaret,
I am so delighted to have been able to help you with this breakthrough!!
In terms of finding birth, baptism, marriage and death records there are two places you can search: Civil Records and Church records.
1. Civil registration began in Ireland in 1864, so you should be able to find any records pertaining to the family back to this date. Civil records are available from the General Register?s Office in Dublin. Here is their website:
http://www.groireland.ie/research.htm
You can also search the indexes to these records online at:
https://familysearch.org/search/collection/1408347
A website that gives good information on civil records and how to search/access them is http://www.irish-genealogy-toolkit.com/Irish-civil-registration.html
2. Church records are the only records of births etc. in Ireland prior to 1864-unfortunately, record keeping in Ireland was not always very good. You should be able to find records of John and Catherine?s family in these records also, if they are available.
Most Catholic records are held locally so you may want to write to the parish priest directly for possible assistance. The civil parish of Boha is part of the Roman Catholic parish of Devonish. (again Irish land divisions can be very confusing!) One website which you may find useful in terms of Catholic records however, is the Irish Times. Here they give an overview of what records are available in specific parishes. For Devonish parish follow this link:
http://www.irishtimes.com/ancestor/fuses/rcparishmaps/index.cfm?fuseaction=showidrecords&CityCounty=Fermanagh&parish=Devonish&churchid=301
With regards as to whether or not their tombstone is still there I do not know. However, I found a Facebook page for Devonish and Boho parish church. Perhaps they may be able to tell you which graveyard you should be looking at and possibly more information. Here is the link to their page:
https://www.facebook.com/devenishandbohoparish
Also, I will pass this message onto one of our volunteers in Fermanagh, hopefully he will be able to give you some information also on what graveyards you should be looking into.
Best wishes,
Emma