Welcome to my forum. What you have outlined looks fine. Good idea to spend several nights in each place. Although I might only spend 2 in the Cork area and then I would stay in Kinsale instead of Cork City. I would add that extra day to Killarney. There is so much to see and do in the SW.
As for the last part of your trip my preference would be 2 nights in Galway and one in Bunratty.
How mobile are your husband's parents? Keep in mind that there are a lot of stairs in Ireland compared to America. Their access rules aren't quite as strict as ours, so many B&Bs have only 2nd or 3rd floor accommodations. Be sure to ask (PS, over there, their 1st floor is our 2nd floor, their ground floor is our 1st floor). Also, most towns, cities and villages are better walked than driven, as parking can be difficult.
Just something to keep in mind! My parents had trouble in some places, and they are only in their 60s.
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May the light be your guide and the darkness be your comfort!