I changed how the threads should go, in a different direction:
[Game] Umineko - Spoilers and speculations: this thread shall serve for everyone who wish to make theories and the like with any information that was retrieved recently (from any media). This will allow everyone to actually focus all theories that were scattered around several threads (even in the anime thread for some bizarre reason).
[Game] Umineko no Naku Koro ni Chiru - Ep. 5 End of the golden witch: this thread should host only posts regarding the episode itself: elements, facts, reviews, comments and the like.
Thus, this will ensure that the first spoiler will be a place for people to speculate with their heart content, while the second should have a more "factual" content.
Creating a "spoiler" thread with solely spoiler from Episode 5 wouldn't practical, since by itself comments and reviews would be a spoiler, so the category of such thread is off.
On the other hand, the stream of so many posts we have seen in the old episode 5 thread are actually a sheer amount of spoilers and speculations.