Question regarding Kellys + Killynagh More Graveyard-Killina , Roscommon

A bit of an odd puzzle/question.

My great-grandparents Thomas Kelly and his wife Elizabeth Beirne are buried in Killnagh More Graveyard, Killina, Roscommon. The headstone (cleaned by my dad last March) reads as follows:

Exact wording of epitaph:

IHS SACRED HEART OF JESUS

HAVE MERCY ON THE SOUL OF ELIZA KELLY WHO DIED 4TH JAN. 1900 AGED 54 YEARS, ALSO HER HUSBAND THOMAS KELLY WHO DIED 3RD DEC. 1915 AGED 72 YEARS. ERECTED BY HER LOVING HUSBAND THOMAS KELLY AND SONS R. 1. P.

Additionally, the Historic Gravestones website had these notes added to the webpage: 

NOTES. To be remembered also:

"Thomas Kelly died 9/10/1954 Aged 73 Years, James Kelly died 26/11/1958 Aged 81 years (both are sons of Thomas & Elizabeth),  James Kelly died 1/11/1933 Aged 89 Years, Kate Kelly formerly Kennedy died 6/4/1936 Aged 63 Years, John Kelly died 18/10/1960 Aged 73 Years"

http://historicgraves.com/killynagh-more/ro-kmon-0460/grave

The section I have emphasized has now been removed from the website at the request of a relative of James, Kate, and John Kelly, who because of lack of records and a DNA match between me and his many generations removed relatives, believes we can not be related and assumes this notation was added in error. While I understand his thoughts, I think that lack of DNA evidence in itself is not exclusionary because after 3 generations matches at higher levels are rarer, and records from the early 1800s are scarce for Roman Catholics. To complicate things, I was contacted by a Kelly who says that she remembers my grand-uncles (Thomas + James listed above) and was told that we are all from the same Kelly family (she is a relative of the other James, Kate + John) so I am confused.

I did contact the person who contributed the photos and info listed on Historic Graves to ask for their source of the Notes section and they weren't sure who or where it was found/provided since it was added many years ago.  They stated it was either from "local" sources i.e. folks from the area or from the Graveyard Register which is held by the caretaker, Eddie Brady of Tulsk.  The Register starts in the year 1952 (after the deaths of my great grandparents and also James + Kate but before the deaths of my grand-uncles, Thomas + James, and John Kelly who all died in the 1950s-1960s).  I was told that the only way to connect with Mr. Brady might be to visit him.

I was wondering if anyone might have some thoughts or insights on this situation?  Such as is there a way to contact Mr. Brady or to view the Register - thinking with the current Covid restrictions ( and I live in the USA) this might not be possible. 

Also, if it is found to be true that James, Kate + John are also interned in the same grave as my great-grandparents can it be assumed that they are related?  Would it not be unusual for others not considered family to be buried together in the same plot? 

Additionally, might there be other records,  ideas, or ways to find out why the originally published notes section stated this info?

Any and all suggestions are gratefully appreciated. 

This is all very puzzling and I would love to establish a link between their (James, Kate + John) father, Patrick Kelly (wife Margaret Flanagan), and my 2x ggrandfather, James Kelly (wife Anne Lanaghan) all of Carrigeenagapul, Kilcooley parish ( with adjourning farmland).

And to clarify, the Kelly person who contacted me knows nothing about my family plot.  She did add that James + Kate's daughter Mary Catherine Kelly "Kate" who died in 1970 ( funeral Mass @ the church in Tulsk) is buried a few plots away in an unmarked grave,  It has been verified that Mary Kate was the first person interned in that plot and her family is not buried with her.