As an author, you captured the spirit of that time very well.
However, there are nuances.
All official signs and warnings are written in Ukrainian. But during the USSR, all official documents and signs were in Russian. Since the Russian language was the official language for all the countries that were part of the USSR (such as Estonia, Latvia, Lithuania, and the other 12 countries)
So, ideally, graffiti like "Привiт" or name of hotel should remain in Ukrainian on the map. But warnings, signs and all what relates to official infrastructure must be used by main USSR language

All what I said you can verify via wiki and photos

Regards
P.S This is a not politian post, but historic one