All this is very interesting about lace curtain vs. shanty Irish! I am abt 7-8th generation in US on my Mom's side, and 4th on my Dad's. In our family shanty Irish meant just what was said above---not only poor, or just recently up from poverty,but they were tough, brawling, lower sorts. Weren't living in shanties in the States but still acted like they were. Had nothing to do with income.
My Mom's family came here in later 18th C due to loss of land to penal laws---may have been better off in Ireland, but had to work hard once here, because of the anti-Irish discrimination. However, they got here so far in advance of the 19th C. huge emigrations, by then they had already done the all-American climb into better educations, professional jobs, etc. They were in NYC & as you can imagine they got into politics too.
My great grandmother sniffed at the Boston Irish--they were all shanty in her opinion! A generation ago, some older cousin was dating a Boston kid & her father wouldn't let it continue---the young man was shanty. His name was John F. Kennedy (However, the girl's father was correct! He was aware of the way the young man's father treated his wife in the fidelity dept & figured the apple wouldn't fall far from the tree. And it didn't).
"Black Irish" in our family meant black hair, and blue eyes & often quite fair skin went with it. I have Black Irish cousins. But whenever my Dad would see an African American actor or singer with an Irish surname, he would joke that the person was "Black Irish!"
As far as lace curtain is concerned, my Mom said it meant partly income & partly attitude---not only well off enough to have lace curtains,if desired (in the early 19th C anyone, Irish or not, who had lace curtains had handmade lace curtains, which were not cheap--factory made came later) but also valuing education, expecting the kids to achieve in school & go to (Catholic) college, etc. The college would have been Cath. because the Ivies & 7 Sisters didn't take many RCs back then.
Quiltersmuse, I wonder whether your pat grandmother & mother had a "normally" strained inlaw relationship & that is where the "haughty" came from? My father's mother used to think my mother's mother was stuck-up, when they first met, but what was actually happening was 2 paralyzingly shy women having difficulty making overtures to each other! They both had been widowed when young, one while pregnant, and both of them were very hesitant in social settings. And my father's mother was acutely aware of the background of her opposite number---the NYC political family history & all that, while she was a fireman's widow.