I just got the hidden item in Iris's when I went back to do the second path, but I'm still missing Mizuki's and #89's if you remember either of those.
Mizuki: This also unlocks another trophy. Lift the fridge, examine and choose the only option on the pot, and the hidden item should appear where adorabbit used to be on top of the speaker.
#89: I believe this was on one of the bookcases/shelves in the corner of the room after lock #3. I just stumbled on this one by accident by hitting x in the general area, I don't recall if it was easily visible