Thank you very much! I'm so glad I haven't disappointed you.
Actually, I have no ideas about their necklaces, but when I was looking through the 6th volume of the light novel I noticed that their necklaces were different. I haven't begun to read it yet.
As for Haru wo Daiteita, have you started with manga or anime? I completely agree that the beginning is really awkward but later it will be quite interesting.