Science Fiction Aficionados discussion

I don't know if this is out of order, but it was suggested that I ask here.

I'm looking for a bunch of scifi stories, whose titles and authors I don't recall:

1) scifi: short: Spaceship crew gets liberty on a planet, but...
2) scifi: short: Humanity realizes it is in a simulation and causes universe to BSOD
3) scifi: short: aliens save two humans from an earth about to be destroyed, but...
4) scifi: short?: water dispute between Earth and colonies...
5) scifi/horror: (GN?) post-apocolypse?, underground dictatorial human authorities... but [spoiler removed] live on the surface


Links are to more details/discussion about each query on the 'what's the name of that book' group.

Or, if you don't want to comment there or here, PM me.