I'm jumping in here & hope to be of help. I think that the Matt (John) & Matt (James) named in GV are consistent with the information given in other sources.
My gr-gr grandfather is the Matthew Ashe (John), of Kinard East & was son of John Ashe & Hanora O'Connor (according to Thomas Ashe's family tree). John Ashe was son of James Ashe/Mary Griffin, again according to TA. My Matt married Mary Doyle of Foheroughmore in 1839 (Dingle Parish records). Their son Matthew b. 1849 (DPR), my gr-grandfather, left Kinard East in 1880 (Citizenship Record) & lived out his life in Holyoke, MA. His siblings, however, remained on the family property & show up in the 1901 census.
The above-mentioned John Ashe had a brother James, according to the TA family chart. James married Ann or Nancy Hickson, & on 26 Jan 1825 (DPR) they had a son named Matthew. This could be the Matthew Ashe (James) mentioned in GV, as he would have been 27 years old then.
However, there is still another Matt Ashe (James) that I'm aware of. The above mentioned James Ashe/Mary Griffin themselves had a son Matthew Ashe (listed on TA chart), who would also have the appendage of James. This Matthew would have been a generation older than the one mentioned above, but could have still been living in 1852. He married Mary Nelligan & I've accounted for 2 of their children in the Dingle Parish records (Matt b. 2 Dec 1827 & Johanna 6 Jun 1830). My recollection is that these children's baptism record says they were born at Kinard. If you need me to check my notes on that, say so.
I can't say which is the Matt (James) on GV, but thought these details might be useful for you. Would love to spend more time on the Ashes but am in the middle of a project concerning my O'Donnells, Sullivans, Cavanaughs, Bakers, & others who immigrated from Dingle & Ballyferriter Parishes to Windham County, VT.