As for Jamey Hanley's original question;
I've been trying to put together some puzzle pieces on his 'James' Downing of Killyberry Downing, b. 1835, and as I've mentioned in this thread, there are numerous clues that he was descended from John Downing of Rowesgift.
There are gaps that need to be filled in with unverified generations, and it's not ethical for any genealogist to build trees based on pure speculation, or uncorroborated evidence, BUT, I often wear my "detective hat" and "put names on a wall with strings attached", just to see how they MIGHT be connected.
Jamey believes that his great grandfather's name was 'John' and that he was born about 1805.
We know from the 1828 Tithe Applotment Books that there was a 'James' Downing, a 'John' Downing, and a 'Widow' Downing, all of Killyberry. We also know from the 1831 Census that there was a 'James' Downing, and a 'Widow' Downing of Killyberry (but no 'John').
We know that John Downing of Rowesgift was assigned rights to 91 acres of farmland at Killyberry by Deed, dated 1 Apr 1734, from his mother-in-law, Anne Rowe of Ballydermot
(see Transcripts of Memorials of Deeds, Conveyances & Wills, 1733-1736, Ireland, Vol 77 ; p. 228 ; Film No. 8088379 ; img 134-135 ; Mem. No. 53470 - Microfilmed at the Registry of Deeds, Dublin)
https://www.familysearch.org/ark:/61903/3:1:3Q9M-CSN1-X3XC-H?i=133&cat=185720 (btw): Rowesgift lies in the Townland of Ballydermot and Killyberry adjoins the northern part of Ballydermot, literally across the street)
Jamey tells us that Edward Downing, son of James (b.1835), was farming 1/3 of the family farm, which he described as "30 acres" (Reply #12 in this thread).
We know that John Downing of Rowesgift had three surviving sons, two of whom held rights to the Rowesgift manor house at various times; Dawson Downing and Capt. John Downing.
We know that none of the descendants of Dawson fit the names and dates to make him an ancestor of 'James' Downing of Killyberry Downing.
We know that Capt. John Downing (b. c.1740) had two sons, 'John' and 'James'. We don't have birth years for them but it's likely they were born between 1765-1775. By 1828, they could certainly have been still living, as could the wife of Capt. John, particularly if she was significantly younger than Capt. John.
Now for some speculation:
1. If 'John' Downing, father of James of Killyberry Downing, (b. 1835) was indeed born in 1805, it's quite possible he was not yet a head of house in 1828 or 1831.
2. Could 'James', 'John', and 'Widow' Downing of Killyberry, have been the two sons of Capt. John and their mother ? answ: absolutely
3. Could 'James' and 'Widow' Downing of Killyberry have been the same two individuals, with 'John' either moving away, or having died ? answ: absolutely
4. Capt. John could certainly have left the 91 acre farm, or part of it, to his sons, John and James.
So, with 'John' (b. c.1765-1775), son of Capt. John, having evidently "flown the nest", I would SPECULATE that James Downing of Killyberry Downing (b. 1835), was the son of 'John' Downing of Killyberry (b. 1805), the grandson of 'James' Downing of Killyberry (b. c.1765-1775), the great grandson of Capt. John Downing (b. c.1740), and the great great grandson of John Downing of Rowesgift (b. 1700).
Makes perfect sense to me, although I wouldn't etch it in granite. All we need is confirmation.