Re: The Hyuuga Family Logic
I think a change of practices may have occured after the incident with Hiashi discovering Neji's brilliance. Hiashi obviously had some guilt about the death of his brother, even though it was Hizashi's choice. Hiashi also saw how being cursed with the seal effected Neji's attitude towards the main family (which, if we think about it, is counterproductive, as the branch family was supposed to defend the main house). Also, Hiashi sees that the first born of the generation is not necessarily the most talented of the clan. I think as a part of his making amends with the clan's history (besides starting to teach Neji himself), he may very well abolish the practice of placing the seal on any member of the Hyuuga.
But of course, if the tradition has to be carried out my guess is Hanabi is not yet old enough to recieve it.