Edited as I see it:
"Crowley was in England in the Thirties when Stephensen’s book was published. When was the article you have about the **Somebody Something** 'zwischen Schopenhauer und Busch' written?"
Smith errs. "When Stephensen’s book was published" in 1930 (technically, written in the 1920s), Crowley was in Kent but only until March 1930. Then he moved to Berlin April 1930-June 1932 and in the mid-1930s too.
From context,
1) perhaps the unknown Hebrew word is a noun "A" derogatorily describing a person. This person "X" is connected to Crowley, supposedly in England at that time in the 1930s. Where is so-&-so, and When is the subtext.
2) The philosophy of X is 'between' (falls in the spectrum between, a mix of, etc.) Arthur Schopenhauer and Wilhelm Busch, presumably: the synthesis was known, conceptually familiar. (I would assume the referent a German here, whereas Regardie's own influences more likely to have been Anglo-American, however.)
3) I am certain Morton Smith did not need to be "fluent" in Hebrew to call you a cunt, Stephen. Friends have shorthand; both Scholem and Smith would have known who/what was meant by the Hebrew here, even if he garbled it.
4) Scholem is trying to figure out something about X; Smith may be in the dark what his name is. X was obviously not introduced, he is known by the Hebrew word A. Trivial issue, but admittedly a point of confusion to you.
With the limited information given, it seems to me that Scholem in late 1945 is inquiring casually of Smith **in Washington DC** about Regardie (a then unknown author, originally from Washington DC), whose Kabbalist work was (re-)published in 1945 and reviewed somewhere (unknown date: Smith asks), and who had a very strong connection to Crowley 1928-32, but after 1942 had dropped out of the occult demimonde. Scholem-to-Smith: 'where is so-&so now?' (British citizen Regardie had been traveling w/ a notorious British spy for several years, in fact; Scholem lived in British Mandate Palestine.) I don't insist I am correct, but this is how the puzzle fits together in my eyes anyway.
Edit: In fact, Scholem saved correspondence from Regardie in exactly this period and owned/ scribbled marginalia in at least one of his books (probably before 1945). But there's more to that personal connection, here ('"The Light is Burning Pretty Low": The 1948 Correspondence Between Samuel Lewis and Gershom Scholem', Correspondences: Journal for the Study of Esotericism 8 (2020), pp.45-72):
Another occultist that approached Scholem, a few years later, was Israel Regardie (1907–1985). Regardie sent a letter to Scholem, on March 4, 1929, from 55 Avenue de Suffren, Paris. This was the address of the famous occultist and magician Aleister Crowley (1875–1947), with whom Regardie studied and served as his unpaid secretary. Regardie presented himself to Scholem as a twenty-one-year-old American, of Jewish origins, who had been extremely enthused by the “Holy Qabalah.” Regardie writes that he is currently “studying under a Qabalist (who is not Jewish),” without disclosing the name of his teacher. He says that he encountered certain problems regarding “Zoharic and Yetziraistic philosophy,” which he believed could be solved by someone familiar with Jewish psychology, an aspect of Jewish esotericism he was not familiar with. Hence, he decided to write to Scholem (whose name he found in Hartmann’s Who’s Who in Occult, Psychic and Spiritual Realms), 36 to ask him if he could collaborate with Crowley, or inform him about other Jewish Kabbalists who could correspond with him in English or French. “I am of the opinion that a Jewish Qabalist of some years experience and study could collaborate with my present Teacher, and much benefit could be mutually derived.” Regardie signed the letter with his magical name in Hebrew letters נחש(=snake) and its numerical value, 358. We do not have any indication that Scholem responded to the letter, and we do not know if he was aware at the time that Regardie was a student of Crowley, whom he considered a “humbug.” 37 However, in later years, Scholem purchased and read Regardie’s first book, A Garden of Pomegranates: An Outline of the Qabalah, which was published in 1932. 38 Scholem noted in his copy of the book that Regardie was Crowley’s secretary, and scribbled many question and exclamation marks in the margins. Concerning one passage in the book, he exclaimed: “nonsense!”
Edit: Another Possibility, Highly Probable instead. The **Somebody Something** is actually Crowley himself, recently arrived in Berlin. On May 3, 1930, a German Jewish journalist Günther Stein had written in the Berliner Tageblatt that Crowley's persona was a cross between Karl May and Schopenhauer = "zwischen Karl May und Schopenhauer" LINK . I get it -- Scholem errs too, but I can see how, in recollection 15 yrs later, he could confuse Wilhelm Busch for Karl May (to fit an existent trope, as I've shown above).
Ergo, now we know: the not-so-mysterious **Somebody Something**, a garbled Hebrew word, was (almost certainly) the 'Beast': תריון. Smith (Episcopalian priest and Biblical scholar) certainly would have known this Hebrew word: Crowley's nick-name.