Sarafan: I'm not a GOG employee, so I don't know on which stage are the preparations to release Quake Enhanced.
But since you are a mod you should have contacts to GOG team people and could ask if somebody (maybe SmollestLight him/herself) would finally be willing to share some infos.
When there are problems getting the update done then why is nobody just telling us "hey people, it might take a bit longer because [insert problem here]." Then we all would at least know a little bit more besides "it will be available here at some point".
I mean more than a month has passed now since SmollestLight announced that the update will be on GOG and that was the last time we heard anything about this from anyone. Clearly they (Nightdive etc.) must have made some kind of progress during this time.
NDAs of any kind also don't really make sense here because
A) the game and its expansion packs have been available on GOG since years now
B) we are talking about an update/patch for a game that has been released 25 years ago
C) the update has been released on many other stores and platforms more than a month ago
Just let people know what's going on. They'll understand it and calm down once they know the reasons. Just be more communicative.