The author has mentioned that Vol.3 is in the works.
My personal theory about the necklace is:
That necklace looks like one half of a whole,
and it’s actually Yukio’s brother who gave it to Komari and he has the other half.
In the flashback for the necklace, the other person has short hair and I doubt Yukio would ever have had short hair.
Plus, they’ll be more angst this way.
Of course, I suck at guessing plots, so I’m probably wrong.
Also, there is an application to be an assistant.
I just like how one of the requirements is:
You must not dislike: Boy x Girl, Girl x Girl and Boy x Boy ero-manga as well as shoujo manga (mandatory)
It’s nice to see that the author is open to all genres. =)