So Sacchan couldn't cry because she couldn't process that Yuzu was gone. But seeing Tanuki Yuzu playing around reminded her of how much she missed Yuzu, and now she can freely cry now. While Tanuki Yuzu isn't Yuzu, she's probably friendly enough to still be a good friend to Sacchan.
Man, the feelings in this chapter is so good. I really feel for Sacchan.
I guess Kouhei and Nana called Kinako because Yuzu went missing? I hope this doesn't mean something bad will happen.