Among the Spektor descendants who have not gotten much coverage here, at least so far, is Bluma Salomonson, the daughter of YES son Benyamin Rabinowitz, who was one of the first members of the Spektor family to go to Palestine.
Here she turns up in the academic paper in Tradition. The author cites a chapter about YES written by Samuel K. Mirsky in the 1958 book Guardians of Our Heritage (New York: Bloch Publishing Company, 1958), which evidently contains excerpts from a memoir by Bluma in which she recalls going to a summer resort with her grandfather, the great rabbi.
The reference to the Bluma material in the Tradition article is shown below. Besides its depiction of the kindly rabbi feeding a cat, and Bluma's comment that "his love for nature was limitless" (both characterizations that strike a chord), the really interesting thing is the uncategorical first sentence: "Bluma Solomonson was the only grandchild of his who survived the Holocaust."
Of course we know this is not true. We know that Benyamin Rabinowitz's grandson and his family survived the Holocaust, but Benyamin's son Israel Isser, Shmuel's grandfather, died in Kovno before the war. We think there is another sister of Bluma and Israel Isser, Yetyl, who lived in Kharkov, Russia, and we don't know her life story.
So maybe Rakeffet-Rothkoff has it right on a technicality and Bluma is the only Spektor grandchild from that side of the family who survived. However, we of course know that Joseph Rabinowitz was another Spektor grandchild who, having emigrated to New York City in 1875 and living to a ripe old age, remained living after the end of the Holocaust. [Correction: Joseph died in 1940, so R-R gets a pass on that count too.]
The obvious conclusion is that Rakeffet-Rothkoff, like other Spektor biographers, knows nothing of the later life of Joseph Rabinowitz. That may not seem surprising except that the author is affiliated with REIT at Yeshiva University. Walter has a theory that Joseph was involved with a group of American followers of Rabbi Spektor. In the paper, Rakeffet-Rothkoff writes about the group under Rabbi Moses Mayer Matlin that founds the yeshiva named for the rabbi in 1897, which eventually evolves into Yeshiva University.
Presumably, if Joseph Rabinowitz had something to do with Rabbi Matlin's project, the historians at Yeshiva University would know something about him. Yet it seems that they don't. So I don't know where that leaves us concerning Joseph's religious activities in New York.
Anyway, I've ordered a used copy of Guardians from Alibris. I'll have it in a week and we will learn what other interesting information Mr. Mirsky has in his chapter. Meanwhile, here is the segment of the Tradition article with the Bluma quotations: