Regarding the funfair, it seems to me like they never went and checked there at all. It feels like SH just threw that out as a reasonable place to search because of 1) children and teenager's attraction to funfairs, a place they regularly socialise 2) there have been many stories of young people running off to join travelling fairs, and 3) the reputation of travellers. So it seems like SH just mentioned the fair to draw attention away from himself and use the traveller's negative reputation to his own advantage. And when he kept talking about the funfair, it sounded like a realistic embellishment of his story to him, and so he kept repeating it.