That's all conjecture. He may want to set off on his own, and may not be well received by the others since he basically hijacked Zatara. When it becomes confirmed whether or not he is, we'll add it then.
That makes complete sense actually. Her father has been taken by Doctor Light, and we don't know if she has any other relatives, where else is she going to live? Just because she's living there, doesn't mean she'll be apart of the team.