This has to do with studio politics, nothing to do with fan fiction.
On the Making of AVP documentary they mentioned 'warring producers'. I assume this is John Davis (producer of Predator) VS David Giler/Walter Hil (producer of Alien).
We all know Peter Briggs script was rejected.
I am wondering if it was David Giler/Walter Hill who vetoed AVP in space, to avoid stepping on the toes of the Alien series, and they reached a compromise where they can set on Earth and make it more of a Predator movie.
Any opinions on this?