You have a lot of variables there!
Remember that the origin port is just that, a port, not where they were born. Given that, the Moycullen area is just outside of Galway city (10minutes) but I would try and research a few more databases before you embark on the area.
Also, remember that your wife's DNA is going to show her maternal line, not the paternal line with much accuracy. I'm not sure which test you used, but if she has Ancestry, she can upload her raw DNA also to www.familytreedna.com but again, they are mostly looking for paternal research areas, but she could upload it to the different family names and see if she has a match.
Also, given the names, most of them are clustered together in Cork area. Kelly, Hennessey, Hennessy would fall together naturally there. Doherty would as well, but it is also a firm Northern Ireland name. You might just do a quick search of the names and dates at www.irishgenealogy.ie A free site that is good for Cork, Kerry and parts of Waterford and LImerick. They are adding new records all the time, so check back with them often.
If you would like specific help with your brick walls, feel free to drop me a line at firstname.lastname@example.org
and I'm happy to walk you through a few steps to see if you need more help or if you would like on the ground help with your travel planning.
Happy New Year and Happy Hunting!