First of all . . . GAH! Formatting!
Secondly, I was going to go through your post point by point but decided against it. I think that a lot of what you’ve suggested isn’t a great fit for the core game of Cataclysm. The astronauts, for instance. The reality is that there’s what, like 80 astronauts out of 7 billion people? It’s not all that plausible for a character to just happen to bump into a spacesuit wearing person in North Eastern America.
So, really, if you want to see these things in the game, your best bet is to make a mod yourself. It’s not that hard to add things like craters and space-junk, or to make an astronaut ‘monster’. I’d encourage you to look at https://github.com/CleverRaven/Cataclysm-DDA/wiki/Guide-to-adding-new-content-to-CDDA-for-first-time-modders and have at it.