Hi Amanda,
Lets see if I can help you. You are lucky in that the name is rare, therefore you most likely can assume that they are all the one family. Alas the name appears to have died out by 1901 there is only one Catherine Bloomer, a widow in Shercock town, she died in The Workhouse in Bailieborough and her occupation was 'Medicant', which meant she lived by begging, therefore it would appear that she had no one to support her. There is one in 1911, but she was an English born governess, working for Lord Farnham outside Cavan town. Taking the information from the marriage cert it would appear that both fathers were still alive in 1869 when Edward and Elizabeth got married. I used Irishgenealogy.ie and looked for the death of John Bloomer and I found one that died and it is registered in Cavan town and its environs, however the image is not available so I am unable to ascertain if it is him or not, so it would be worth your while to purchase a copy, in order to rule him in or out.
Name JOHN BLOOMER Date of Death 1873 Group Registration IDN/RSR District/Reg Area Cavan Deceased Age at Death 52 Returns Year 1873 Returns Quarter 1Returns Volume No3 Returns Page No 67
Photocopies or official certificates can be obtained via the following link.
I also looked at https://genealogy.nationalarchives.ie for any wills, but I could find none. I looked up Griffiths valuation at http://www.askaboutireland.ie/griffith-valuation/ and it shows John in 1856 renting land from Mr. Reburn in Latteriff. In 1827, there are 2 John Bloomers found in the Tithe applotments http://titheapplotmentbooks.nationalarchives.ie one in Cullies (also called Drumhillagh) and the other in Knocknashammer, neither townlands are too far apart. Griffiths and Tithe Applotments are both land records, which just tell us where they are is in occupation for those years.
With regard to Thomas Fox/Faux, in the 1901 & 1911 Census, there is a Thomas with his wife Letitia and Canning nephews in Kilcrossduff, this family had no children and it would look like their nephews were assisting them with the farm and most likely they would inherit this farm from them. Again I found a death for Thomas Fox/Faux without image, so you might decide to get a copy of same. Look for deaths in Bailieborough area, it covers the Shercock area, though Cavan & Monaghan town has hospitals and sometimes people ended their days in hospital. Here is Thomas & Letitia marriage details Party 1 NameTHOMAS FOX Party 2 Name LETITIA PEPPER Date of Event 30 April 1879 Group Registration ID2653871 SR District/Reg Area Cootehill, Thomas was a brother of Elizabeth Bloomer and most likely Thomas Senior was still alive in 1879.
It might be worthwhile taking out a subscription with https://www.irishnewsarchive.com look up The Anglo Celt & Meath Chronicle and you might find more details regarding their family ie. sale of land, deaths etc. I have found in my own family that deaths that were not registered were mentioned in the local newspapers by way of passing sympathy to extended family members etc.
I may have more information but alas I am renovating my home and I dont have access to my books etc. Also look at the Flax Growers List for Co. Cavan at https://www.failteromhat.com/flax/cavan.php on this you will see that there are 3 Bloomer men in 1796 in Killann, this place would be close to all the previous places mentioned. You may also wish to take out a subscription with Roots Ireland and see what is available there, I did a quick look up but did not find much more than above.
Please let me know how you get on. Regards & best wishes Carmel O'Callaghan