For Kurumi's dream: I wonder if the person behind the twitter account is really Isanuma, or if it's her short friend doing it. Kind of like a foreshadowing thing. As for the whole thing with Naoi being a stalker, IIRC Kuwabara wrote a oneshot before called "Ultra Stalker" and I think Naoi resembles the main character of that. Plus, Naoi's supposed to be like a cat and cats like to play and stalk things.
For the leaflet: Kimura got a name before either of Isanuma's friends. She's had 2 cameoes in the main story, so I wonder if she'll become relevant later on. Introducing a character who seems to develop a crush on Naoi feels like her role could end up being for Kurumi to learn to deal with jealousy given that Kurumi is new to the emotions that come with being in love.
And for the notes page, it got me thinking. Next volume is the third volume, and Naoi's surname is associated with "honesty". There's a saying in Japan, "三度目の正直" (Sandome no Seijiki) that can be translated as "Third time's the honesty". It's basically the Japanese equivalent of "Third time's the charm". So it's possible that volume 3 could end up as a Naoi-focused volume as Kurumi gets to know her better.