I am pretty sure that the answer arc and the question arc show the same sequence of events. I think it's great the anime wastes no time showing again many scenes from Watanagashi, this time from Shion's PoV, but just mentions the things the viewers already know.
Spoiler for Observations after watching the sub:
So Takano gave her notebook to Shion, one year later it seemed Shion has lost interest in the mystery but Takano persevered and told her about the breaking in. Why? Sure, she should have known Shion doesn't exactly get along with her family but what was the use of taking her to the warehouse? Maybe Takano actually planned Shion's "insanity" (hearing strange noises and so on) and counted on her to lose it and kill a few Sonozakis? Way too complicated scenario, yes, but I have begun to expect pretty much everything from Takano.
Right now, the obvious scenarios seems to be Shion overpowering Mion and taking her vendeta with the Three Great Families to the extreme. But since this is Higurashi, what is obvious is rarely right.
