You kinda hafta tell the players that the published data - whether Mongoose, Travellermap/wiki or elsewhere - is unreliable, incomplete, and sometimes downright wrong. They may have better information themselves (this kind of thing is what knowledge skill rolls are for), or not. The PCs can, do and should still read up when going new places - its (usually) better than knowing nothing - but expect surprises. Even if their info was correct when they got it, it might not be any more.
In a big universe with slow communication it is normal to have old, bad information about other places. Also, these places are really big: whole solar systems and planets with billions of people, so there is a lot more going on than the two paragraph planet blurb can encompass. LOTS of space to tell any kind of story you want really.
So using published data still allows the referee - indeed really requires the referee - to make it their own in order to bring it alive. Interpreting and filling out what is already there is enough work for me, and probably for most referees. And if PCs go somewhere unexpected, it is nice to have at least some minimal amount of data on it to improvise off of, until you get a chance to prep.
For this reason, it would be nice to have at minimum Travellermap/wiki data on Foreven, or even better an actual Mongoose book. Of course, we can just steal someone else's Foreven, but it is nicer if it is all there on Travellermap as this is what the players look at.