Thylacine, the article is written by a journalist with quotes taken from a conversation with Fehon. As a body of text it cannot be taken as wholly accurate, as the journalist is adding his own story to join up Fehon's quotes.
In such articles, even the quotes
could be taken out of context if a journalist wanted to. I'm not saying that's the case here, just that a body of text with intermittent quotes cannot be taken as a good summing up of the case so far (albeit the best we have been given) to the point that we should no longer be going over 'old ground' as such.
Going over old ground is what investigators do. We all have little to go on here. I wouldn't want the conversation to end here just because the article you posted a link to sums up everything....for some people.
"We dont know, either, Fehon says. Thats why we are keeping an open mind to all 

*sibilities.
With regards to the 'errand' - I can see nowhere in the Australian article that the possibility of the boy travelling in the car on that errand has been ruled out, do you? I was pondering the what, where, why aspects of the errand as something that
I am interested to know. I realise that the LE have more knowledge about this than I do..but still I am curious.
Jmo