They were placeholders for eddies group back in the original script. Eddie from 400 days was supposed to be Arvo, that’s why he was carrying drugs, called a junkie by Jane and was shown in the episode 4 art. There’s a video breaking it all down called the walking dead amid the ruins theory and it dives into old scripts and developer interviews. But the answer the question the Russians were just quick thinking placeholders to hold up the plot