I have been looking at the timeline of the morning WT was taken.
IMO the two parked cars left and returned after FD went into town.
FM has said that early that morning she opened up curtains to sliding door onto back Verandah she looked out saw two cars parked on road, thought strange but went on with the morning breakfast, organising day, kids playing with toys etc.
9.00am
FM, William and sister riding bikes on driveway, FM notices car drive past do uturn and drive out past them. Kids were probably waiting to say goodbye to FD when he leaves for town.
9.15am
FD goes into town for better reception.
9.15am - 10.25am
FM, GM, William and sister go out to side deck and yard. FM takes William down to tree to climb and play tigers. FM notices cars are still there. FM and William go back up to deck to play with GM and sister.
At some stage FM goes inside to make tea, after several minutes she realises she can't hear William, he is gone
I am sure the FD would have seen the two parked cars when he left but it does not seem so. IMO they left and retuned.
I wonder why they think William would run down to the road if he was expecting FD. IMO I would think he would run to the driveway it was close to where they were playing and that's where he saw FD leave.
I know they said the kids would run to greet FD back at home, but I would think they would run to driveway not the road.
IMO William would have to be lured too the road. If William had of seen a car like FD and it slowed down he may run down and realised to late it was not FD
I believe BS is involved in someway. Just a thought (crazy hopefully) if there was a Pedo ring
in the area and BS is part of it maybe his part is to be like a spotter, he works at family homes and would see a lot of children.