Victor Fet responds:

 

As a remote outside observer of Luzhin etymology, and a native Russian speaker, I would say that there is really nothing in
both books that distinguishes Dostoevsky's Luzhin from Nabokov's.

 

One does not know from the context whether the name comes from the town of Luga or from "luzha" the puddle.

 

There is also a third possible connection, not discussed here yet.

 

My personal linguistic emotions always connected  Luzhin name (at least in Dostoevsky's less pleasant character) with a Russian adjective "LUZHENYJ" (tin-coated, tin-lined), derived from the verb "ludit" (to coat with tin). Indeed it is the only Russian word starting with "LUZH.." other than "luzha" and related "luzhajka".

 

Tin-coating was a popular street craft in Dostoevsky's time, and there is а classic image of a  tinker ("ludilshchik") man coming to inner yards of St Petersburg houses with a call "ludit'-payat'!" ("tin-coating, soldering!"). It was a common Gypsy occupation in Russia.

 

More important, a very common derived idiom "LUZHENAYA GLOTKA" ('tin-coated throat") meant "he has a good pair of lungs", which Dostoevsky's outspoken Luzhin clearly fits--he is nearly the only strongmen in C & P.

 

Etymology in Russian may be tricky, and we can read meanings into it -- but judging from the context there is nothing that tells the cocktail Molotov from the original hero of Pomyalovsky's novel "Molotov".
Or a Lensky from a Lenin.

 

 
Victor Fet