Livre d'Or

Some good points here. A little linguistic nitpicking:

I did get to meet some Somali Bravanese Muslims, an ethnic minority from Somalia via Kenya whom I hadn't encountered before.

Interesting. I encountered them once via the NNLS, I think.

Anyway we had some very interesting discussions, including around the use of language. Some of the Muslim participants said they didn't like what I had thought of as an otherwise neutral older spelling, Moslem. They said they associate that spelling and pronunciation with people like Donald Trump

Whilst it might be an older spelling, I think it reflects a difference in how you pronounce Arabic. If you say "Mohammed", you'll say "Moslem"; if you say "Muhammad", you'll say "Muslim". The latter is standard Arabic; I think the former might be Egyptian. OTOH, that doesn't necessarily say anything about its use in English.

I'm not that happy with Jew as an adjective either.

Technically, this usage is as a modifier (i.e. a noun being used like an adjective).

It's a slight simplification but I think that probably is true for the Yiddish equivalent, Yid

ISTR recall reading somewhere that in Yiddish it's always pronounced with a long I, yīd which distinguishes genuine Yinglish use from derogatory English use. But I've barely ever heard the Yiddish word in the singular (though the phrase "a frummer yid" springs to mind); it's almost always yid(e)n in the plural, and used in Yeshivish.

It makes me feel like I've time-travelled into a nineteenth century novel where people use elaborate circumlocations like gentleman of the Mosaic persuasison because Jew is basically synonymous with loan-shark.

As I understand it, in the nineteenth century, "Jew" referred to ethnicity, "Mosaic" to religion. Hence I remember reading, many years ago, about someone being described as being Polish by nationality, Jewish by people and Mosaic by religion.