First to address the name in question. The name in the subject line is spelled with "shch", which is frequently used as latinization of a Russian letter "Щ", which looks similar to letter "Ш" (SH). The Russian sound, represented by "щ", sounds like sh and ch blended together. With this spelling - Мощенник - the root of the word implies that it's a person who paves roads, but I don't know if pavers were ever known by this word. Мощеная дорога (paved road) or мощенная булыжником дорога (cobblestone road). All searches for this word online return the context equal to moshennik - swindler.
Fred, would you be able to post a photo of the original page with this name?
Moshennik is not an anti-Semitic word and is not used as such, Russian language has far worse words for Jews. Its root comes from the word moshna (leather money pouch with ties). Russian - moshna, Polish - moshnya. Moshennik - someone who steals a moshna. Moshonnik - maker of these type of money purses. These words, with the exception of "moshennik", have been out of use for a long time, as no one keeps their money in leather pouches or makes these pouches for a living.
Also, "son of Moses" is not a thing either. Orthodox Christians (Ukrainians, Russians, etc) very frequently had Biblical names, unlike Jews, who had Yiddish names. In late 19th-early 20th century Jews frequently used Russian-sounding equivalent names, until these names became known as "Jewish" names in Soviet Union. At the same time these names fell out of use with non-Jews:
Jews - non-Jews
Movsha/Moshka - Moisey (Moses)
Avrum/Avram - Abram
Ios/Iosel - Iosif
Sura/Sora - Sara
Duvid/Dovid - David
Yankel - Yakov
cursive ' ш ' can look like the cursive ' ж ' (as in the 's' of 'usual'). On that basis the word wouldn't be мошенник but rather it would refer to someone of the Mosaic faith ie Moses which i take to mean Jewish.
I'm not sure what you mean by this - are you saying that Moshennik spelled with Ж (Моженник) means someone of Jewish faith? Not sure how that's the case, there is no such word. Moses in Russian is Moisey (МОИСЕЙ), there is no Ж there. The word for Jews in the census/metrical records was universally iудей/иудей (iudey), related to Iuda/Judah (as in a Jew). In Russian language iudey refers to someone practicing Judaism, evrey - someone of Jewish ethnicity. Ethnicity was not much of a thing in Russian empire, people were tracked by their religion and they belonged to their locality's religious society - as in "registered to Minsk Jewish society". In Russian empire once a Jew converted to Christian Orthodox faith, they gained all benefits of society, unavailable to Jews. There are references to Jewish ethnicity in some WWI records, but mostly all references are to faith, not ethnicity. In Soviet Union the emphasis was on ethnicity, rather than faith, as religion was nearly outlawed. Documents (internal passports, job personnel records, classroom rosters, etc) had a entry field for ethnicity (also known as the infamous 5th entry field, used as a clear marker for discrimination).