1) The reason why I didn't just call these scenario outright "parallel universes" is because of this. When people think of "parallel universes", they tend to imagine worlds that are
completely different from each other. This is
not the case for Higurashi. Like I mentioned in the post linked above, "the characters and settings remain exactly the same thoughout all the scenarios". In other words, the "world" itself remains the same. The difference are the events that occured within each world.
However, just because an event wasn't shown in a scenario doesn't mean it didn't happen. For example, in Onikakushi, a mystery would be "how did Mion find out about the conversation between Keiichi and Oishi?":
"Keiichi+Oishi conversation" → ? → "Mion finds out"
Now, we learned the fact that "Shion/Mion worked in Angel Mort" in Watanagashi-hen. With that, we can "equip" that knowledge onto Onikakushi-hen and finally fill in the missing blanks:
"Keiichi+Oishi conversation" → "Shion worked in Angel Mort" → "Shion told Mion about it" → "Mion finds out"
or (depending on your theory)
"Keiichi+Oishi conversation" → "Mion worked in Angel Mort" → "Mion finds out"
Even though the conversation that took place between Oishi and Keiichi in Angel Mort happened in Onikakushi-hen, concrete "facts" (not events) can be applied throughout all scenarios.
The world is the same, but the developments are different. The cause for this deviance is based on a pretty simple principle. So far I have avoided the usage of that critical word, but hopefully you guys will notice it yourselves.
2) See the points raised in my post here:
http://forums.animesuki.com/showpost...&postcount=173
Like I said above, these scenarios are independent, but they are all related. The purpose for these different scenarios is to give you a view of the "overall story" from multiple different angles (multi-faceted view, like I mentioned in the other post). With only one "view" (scenario), you can only see one side of an object (world), but with multiple views from different angles, you can then try to build a 3D image of the object in your mind. The object (world) itself remains constant, but your recognition of it will change over time as you learn more about it.