Speaking of the Bohemian lady (whom d'Onsky married after his duel with Demon Veen: 1.2): I notice that Bogemsky ("Bohemian") was a penname of Chekhov's younger brother Mikhail (1865-1936). He used it when publishing his stories in Detskiy otdykh* ("Children's Relaxation"). In a letter of September 21, 1886, to M. V. Kisilyova, Chekhov writes of his family's life in Moscow and calls his brother "Bogemsky:"

Ма-Па [Maria Chekhov, the writer's sister] видается с длинноносой Эфрос, дает в молочной** уроки по 7 коп. за урок и берет у Богемского уроки по географии, которую дерзает преподавать. Боже, отчего я не преподаю китайского языка? ...Богемский, он же финик, рисует виньетки по 3 руб. за штуку, ухаживает слегка за Яденькой, бывает у Людмилочки, надоедает всему миру философией и спешит съерундить другой рассказ в «Детский отдых».***

The author of "The Duel" (1891), Chekhov seems to have served as a model (at least, to a certain degree) for Ada's husband Andrey Vinelander.**** Like her mother, Ada is an actress; in 1901 Chekhov married the actress Olga Knipper. Btw., Mikhail Chekhov's marriage collapsed at the last moment: his bride ("little Countess") suddenly married another. Mikhail Pavlovich shouldn't be confused with Chekhov's nephew Mikhail Aleksandrovich (son of Chekhov's elder brother who published stories in Suvorin's Novoe Vremya), an actor of genius and famous director (who left Russia in the 1920s and, in fact, might have served as a model for Odon in Pale Fire).

**Chekhov's calls molochnaya (dairy) the Moscow gymnasium of Mme Rzhevsky (whose relatives owned a milk farm and milk shops). One is reminded of a quite accidental milkmaid who entered the scene during Demon's duel with d'Onsky. Incidentally, this duel took place in Nice, and Chekhov often spent winters in Nice (the fact mentioned in Ada: 2.9)