Yes, this is basically why I've never warmed to her.
And yet, however,
This! While ever this photo remains as the proof that William was alive and well at 9.37am that morning, I just can't believe they did anything to William. It's just not possible to murder/be responsible for the death of a child and then dispose of the body and the evidence so well that when a swarm of cops and volunteers and SES are there within a couple of hours they find or see nothing at all that calls them into question. Do parental figures murder/kill by negligence children? Yes, sadly, with some regularity. But they generally give themselves hours and hours if not days or even months before reporting it. Not half an hour or so.
The only way its possible is if this photo is such a good fake that even the forensic examination of it was fooled, and I really doubt it. They're criminal masterminds if so.
<rsbm>
One of the things I come back to in this case is that, if the is confirmed at 9:37am, whatever happened to William it was either a criminal mastermind or insane "luck" (I don't like using the word here because it was insanely unlucky for William) that they got away with it, so the lack of likelihood of something based on the amount of time to do it, provided it can't be ruled out, doesn't really make something more or less likely than anything else. (There's my word salad contribution for the day.)
If the FPs story is believed then a predator just happened to be on the street at the exact time he ran around the house and in the space of a few minutes had gotten him into a car and driven off or grabbed him and wandered into the bush, and not one person heard or saw anything directly. This wasn't suburbia, but it wasn't the back of beyond, either. If the FPs story is not believed then something happened to him in the house and it was covered up in a relatively short space of time. In my view (and obviously everyone will differ on this), there's not a lot of difference in the unlikeliness. Neither are impossible.
I had the abduction theory as more likely until the information about the FM's drive came out at the inquest. It was partially the absence of this information in interviews - I had heard interviews about that morning and they were all so specific, right down to the order of the activities the kids participated in and what happened after he went missing - specific to the point that every minute was accounted for - and yet the drive was left out.
There are explanations for this that are not sinister. My first inclination was that she had forgotten due to the trauma, which would be completely normal. But then, why was she so certain about everything else? The other explanation is that she was told to leave this information out by police for some reason. But it wasn't like there was a gap in her stories that accounted for this - it actually didn't fit with the way the stories had been told in the interviews. She always said that she'd been running around looking and then got a text from FD saying "home in 5" and had calmed down a bit as a result. So I didn't think "oh well she clearly lied" but I did think her evidence was at that point unreliable.
It also made me realise that there was more time to do things than originally appeared. Maybe there wasn't more actual time, but she wasn't running around like a headless chook for it. The time wasn't used up by looking in cupboards and around the house, either; it was utilised by a drive down the road. For me that gave a very different perception of what was going on in that time. So at that point the theory that something happened at the FGM's house became as likely as the abduction theory to me.
The car actually helped form my theory on what happened if it was at the FGM's house: William did in fact disappear as stated. He ran around the house and into the car or something near it so hard he injured his head and was killed instantly. FM goes looking for him and finds him, and realises he is dead. She panics, because that's her whole world gone, not just losing William but losing his sister. She puts his body in the boot. There's no blood or anything like that because you can be killed by a knock to the head without bleeding. She goes back to "searching", her mind ticking over what to do. After a few minutes she comes up with going for a drive to "search" to dump the body, which she does. She figures if he's found then it will look like someone took him and killed him. She rationalises it in her mind that there was nothing she could do anyway, and it was better for his sister not to be taken away from them. Nobody else has any awareness of this, hence their stories are consistent with the official story about the disappearance. It could all have happened, without a trace, in 20 minutes.