I sure don't mind that idea. Sounds like fun. =]

And yep, he won't be taking initiative in talking to anyone other than Haku or Miku; he'll likely hide behind the nearest one if anyone else tries to speak with him. Even his close friends. (On that note, I wonder if I should selfcest at some point and bring Momo to he party so he can withdraw from her and create more horrible. XD)

Haku going passive creeper yandere easily makes this better.