pg. 281 — Bakhtin Mikhail Bakhtin (1895-1979) was a Russian philosopher, literary critic and scholar. He was an active part of academic discourse in the Soviet Union in 1920s, and after his suppression, his ideas were rediscovered in the 1960s. This fact, in addition to Bakhtin's appeal to an intellectual like Geiger, are probably why Geiger recommends him to Innokenty.
pg. 284 — Carthage, which should have been destroyed, and that senator (what's his name?) Carthage was perhaps the Roman Republic's greatest enemy and it took the Romans three wars (the Punic Wars) to conquer them. Roman Senator Cato the Censor was known for ending all his speeches with the phrase "Carthago delenda est," which translates to "Carthage must be destroyed."
pg. 288 — the Virgin This refers to the Virgin Mary, who was the mother of Jesus despite being a virgin. This could tie into The Aviator in that Platonov, like Mary, has done something against biology - Mary mothered a child despite being a virgin and Platnonov has managed to see the 99th year after his birth despite physically being in his thirties.
pg. 300 — the parable of the prodigal son In this story, a father has two sons and the second son asks for his part of the inheritance before his father dies. The father gives him the money, but the son is prodigal, i.e. a spendthrift, and he wastes it all and becomes poor. He returns home and begs his father to accept him back into his household and, to his surprise, his father happily welcomes back and throws a celebratory party in his favor. This is a story focused on love and redemption, which ties into Innokenty's situation and the following paragraph in which he extols the virtues of mercy and love.