After searching yesterday through archived New York newspapers to find any mention of Uncle John's in-laws using their assumed surname Hark, I decided to go through the whole process once more for the original surname, Aktabowski. After all, I might have missed something.
What I did miss was the sense that far more of the family had chosen to go the name-change route than those who opted to remain with tradition. Even in the families of the oldest of the Aktabowski siblings who had kept their original surname—John's wife Blanche's two oldest brothers—their own sons later decided to go with the more streamlined Hark alternate identity. There were so many who had preferred this sleeker image that I could imagine them all whining, much like complaining teenagers, "But mom, everybody's doing it!"
That, of course, meant that for each descendant, I needed to pinpoint just when the name change occurred. The problem with that plan was that I had seen very few of this family who appeared to have an official sanction permitting such a legal change. I had to go back and double check: just who can change their name, how can they do so, and where would I find such records.
In the process of this inspection, I found plenty of guidance online. There were case studies on difficult-to-trace sources of aliases. Getting closer to the crux of my own research project, I even found an article about the difficulty of tracing name changes among Polish immigrants. I found helpful tips from state archives, such as this article from the Massachusetts Archives on documents in their holdings specific to family history—especially their subheading on documents related to name changes.
One way immigrants to the United States can officially change their name is through the naturalization process—but not all of the name-changing members of the Aktabowski family were immigrants. Many of them were native-born citizens, and had made the choice to change their name well into adulthood. The problem was, I just wasn't finding any record of such changes.
Granted, according to the FamilySearch wiki on the topic, there are a few resources for searching through the court record index in the pertinent county location in New York. Ironically, the only Aktabowski in-law whose name change I could pinpoint to any court record was that of Uncle John's New York native sister-in-law, Theresa Aktabowski, who had married an Italian immigrant—Antonino Cappadona—who asked for a name change to Thomas Captain once his citizenship request was granted.
As for the one legal document I've been able to find referenced for any of the Aktabowskis themselves, it was through a newspaper report, just as an article at GenealogyBank had suggested. A son of the oldest Aktabowski brother had petitioned the court for a surname change to Hark. Gerard Aktabowski made that request in 1945, when he was twenty two years of age. But he didn't make it in the city in which he had been born and raised, but in Palm Beach County, Florida. If it hadn't been for that newspaper being included at Newspapers.com—and my subscription linking that service with my Ancestry account—I would never have known to look for such a record in Florida.
The fact that so many of the Aktabowski family had changed their surname made for an interesting readout when the Queens borough Daily Star published the guest list for Uncle John's daughter Frances' wedding in its August 27, 1929, edition. Uncle John's Laskowski relatives' names mixed in not only with Frances' groom's Hanlon family, but with both Aktabowskis and Harks, and even editorially-incorrect "Horks" as well. At least now that I'm working on this branch of the family history, most of those are names I can pinpoint, regardless of the way each relative chose to represent that surname.