(Higurashi spoilers) Well, in that case the question is how did they know where the body was? Also, I don’t remember Keiichi mistaking passers-by as Teppei. But in any case, I don’t think this was the error, so this isn’t really the right thread for us to discuss it.
All in all, I find the references to the Higurashi ‘game board’ in Umineko illogical at best (ironically) and potentially Higurashi-ruining at worst.