Blakes from Derrymihan, Holihan? Neils

My gr grandmother was Julia Blake. I live in New York State.   Recently from DNA evidence, I have been connected to the West Beara region and I have reason to believe that my Julia was one of two by that name born at Derrymihan (with its many spellings!).  I have also discovered a John Blake buried in Fall River Mass USA (where Julia wound up) whose gravestone says "native of Derem..(illegible), parish of Kilacon...Cork"

The first possibility is Julia Bleake born to Jeremiah and Mary Neil in 1838.  The second is Julia Blake b to Daniel and Margaret Holihan.  I am leaning toward the father as being Daniel for several reasons.  Julia's death certif says Daniel (but gets her mother completely wrong...another story).  Julia's second born son was named Daniel and her second born daughter Margaret.

Using Rootsireland, I have also found 2 other children born to Daniel and Margaret: Catherine Blake, 1828 and John, 1831.  I believe that both Catherine (married Jeremiah Shean in Rhode Island) and John eventually lived in Fall River.

As for the Jeremiah Blake and Mary Neil, I found one other child:  Jeremiah, b.1834.  Then, a Jeremiah and a Honora Neil had a series of children, beginning with John in 1842.  Michael, 1843, Stephen 1844, Mary 1848, Mary and Peter,1853,  Jeremiah 1860 and Michael 1867.  Could it be that first wife Mary died and he married her sister, Honora?  I am interested in these children of Jeremiah Blake and Honora Neil as I know that Stephen went to Fall River also and Julia and her husband (Edward McDonald/Donnell, Kildorrery Cork) were godparents for several of Stephen's children.

I am hoping that you may have family files on these families, or correspondence from others to shed some light.  I'd like to learn more about Margaret Holihan and her family.  Was Derrymihan a very large townland?  Is there anything more that I can learn about Julia (who I believe came to the US in 1847).  Is there a way to learn if I have DNA matches in Ireland?

Thank you for any help that you can offer!

Elaine Massena, White Plains, NY