are almost certainly referring to the Airgíalla, Síl Daimín, Síl Duib Tíre, Uí Crimthainn and the Bregia Ó Cellaig.
AT999.7 Maelseachlainn Ó Maelruanaigh, king of Cremthann, was slain by the Uí Ceallaigh, i.e. Cú Caille. https://celt.ucc.ie/published/T100002A.html#p352 AFM998.8 Maelseachlainn Ua Maelruanaidh, lord of Creamhthainn, was slain by the Ui-Ceallaigh. CS999.8 Mael Sechnaill ua Mael Ruanaidh, king of Cremthann, was killed by the Uí Cellaigh, i.e. Cú Caille.
Annette Kehnel's work is very interesting. I have not come across it before, nor many of the annals entries referred to in it.
But let me be clear, Uí Maini === Ó Cellaig by centuries of definition. I assume the title comes from The Book Of Lecan itself - The Tribes And Customs Of Hy-Many, Commonly Called O’Kelly’s Country. But if not, it still shows the inherently assumed association. All the genealogies are arranged around the Ó Cellaig. This is why I say there is only one genetic Uí Maini family, and that is the Ó Cellaig.
In order for the genealogies to correlate to the Y-DNA as much as possible, there is only one reasonable conclusion with the data we have to date, and that is R1b-DF105 are the Connachta. The only way that R1b-A18726 AND R1b-BY35731 can both be Uí Briúin, is that R1b-A18726 are the descendants of Dau Galach and R1b-BY35731 are the descendants of Conall Oirbsen, the only 2 sons of Brión mac Eócháda Muigmedúin that Dr. Bart Jaski, for one, found credible.
That fits hand-in-glove with R1b-ZZ87 being the Uí Néill, and R1b-FGC23742 and R1b-BY35727 being the descendants of Fiachróe Foltsnáthach's 2 sons, Feradach Daithe and Amalgaid, respectively. Again, we don't have all the mutations discovered yet, and we are seeing that many of the smaller direct subclades of R1b-DF105 are being brought under the umbrellas of the larger direct subclades. For example, R1b-A10642 and R1b-FT17642 were just moved to under the R1b-ZZ87 Uí Néill umbrella clade.
So as you said, by the principle of Occam's Razor, R1b-DF105 are the Connachta. It fits too well to be anything else. Then R1b-A18726 must be the descendants of Dau Galach for the reasons given above. Then R1b-A259 are clearly the descendants of Eógan Sríab, who is only ascribed one son; which leaves all the other direct subclades of R1b-A18726 being the descendants of Ernán, Eógan Sríab's brother, who is ascribed at least 3 sons. Therefore, the R1b-BY198 men are Uí Briúin.
The R1b-BY198 clade did not occur until after Brión mac Eócháda Muigmedúin, who was not born until a few generations after the fictional Domnall son of Fiachu Sraibtine AND the fictional Eóchád Doimlén son of Cairbre Lifechair. Plus, the "Uí Maini" families are appearing in several different Dál Cuinn clades, as noted in previous posts. If they were all in R1b-BY198, then it might be something to consider; but they are not. So we are back to an "Uí Maini" confederation, NOT a dynastic group; which breaks all the Uí Maini genealogies. Yes, this does give rise to the question as to who were the Uí Maini in the early annals entries before the rise of the Ó Cellaig; and for that I have no answer as yet.
I intensely dislike having to diverge from the genealogies and annals, but there is clearly a significant tangle in them based on the Y-DNA results. The Uí Briúin Aí genealogy is obviously wrong, based on the Y-DNA. The Cland Maíl Rúanada genealogy linking them to the Uí Briúin Aí is obviously wrong, based on the Y-DNA; but they ARE appearing as descendants of Fergus, which does fit their early genealogy. And so it is crystal clear that R1b-FGC5939 are NOT the Uí Briúin Aí. There were obviously later political affiliations, but not a direct genetic connection after the split under R1b-A259.
So yes, the southeastern portion of Co. Galway has major genealogical issues. I am attempting to reinterpret the records only where necessary to fit the Y-DNA. The Uí Maini, unfortunately, are one of the worst of these tangles.

