>>>>>CHW also mentioned "nikto b", which the Russian speakers
>>>>>have ruled out.  I think.  But I'd like to clarify this
>>>>>last detail: if someone asks "Who is Botkin?", is "Nikto
>>>>> b" an absolutely unidiomatic answer?   

Yes, it is absolutely unidiomatic combination and has to be ruled out. 

If to "Who is Botkin?" one wants to say "nobody", the answer is "Nikto";
full answer is "Botkin is nobody", or "Botkin - nikto" [the verb is
omitted].

Russian "b" is just an abbreviated particle "by" (like in "Nikto b[y] ne
podumal", "nobody would have thought") but "nikto b" does not have any
independent meaning.  

I brought it up but only as a possible palindrome with first name
"Nikto" = "Nikto Botkin" or  "Nikto B."  (B also being, naturally,
Cyrillic "V" for Vseslav or Vladimir).  

There is also a traditional K/Ch interplay between down-to-earth pair
"Nikto" (nobody)/"Nichto" (nothing), versus more elevated poetic "Nekto"
(someone)/"Nechto" (something).

Victor Fet