Re: another quibble
Earth would have John and Mary, but this almost-Earth has "Jahn" and "Miri". Exactly like Earth, but not quite.
Perhaps their real names ARE John and Mary, but they are so old that they have forgotten how to spell them? Use of language does tend to drift over time, perhaps this extends to people's names as well.
It is by caffeine alone I set my mind in motion. It is by the beans of Java that thoughts acquire speed, the hands acquire shakes, the shakes become a warning. It is by caffeine alone I set my mind in motion.