Compilation of
the official sources

*1 the meaning of the russian word “сухарь” (4) (dry & insensitive person)

*2 the word “Мещанин”/”Meshchanin” (“Mieszczanin” on Polish) doesn’t seem to have a good equivalent in English.

On Russian this word has 2 meanings at the same time:

1) In Tsarist Russia: the image of the urban class, made up of small merchants and artisans, lower employees, etc.

"Мещанство"
2) A person with small interests and a narrow worldview, narrow-minded person.

"Мещанство (характеристика личности)"

I couldn’t find a good equivalent on English that would cover both meanings at the same time, but the best alternatives are “Bourgeoisie” (a social class similar to the one I mentioned, also “Bourgeoisie” was sometimes translated to russian as “Мещанин”/”Meshchanin”) together with “Philistine”.

I mentioned only the “Bourgeoisie” because I think the book was placing higher emphasis on the social classes.

*3 "зевака"