Horrible to think about what may have happened.
I can't decide who I think is guilty of actually taking him, Bill or Tony.
I think if Bill took him, then what you JFW said could have happened & he could be alive somewhere, in god knows what kind of situation..
It is too coincidental his past accusations (even though his victims were female), his being at the house days prior, the police attention on him (we know they know so much more than we do).
If Bill took him, he would have definitely passed him on to someone else, maybe held him in that pawn shop first.
I think if Tony stumbled across him, it was accidental, he was in the area maybe checking out the empty houses, or stealing the wheel rods from the bins & happened to cross paths with little William. If he took him, with what his family claim, that he arrived home drunk that day, I hate to think what he did, but I don't think William would have left his company alive, almost like with Daniel, the opportunity just presented itself & he took advantage of it.
I really hope it's a completely different situation too, & that someone is loving him & caring for him, either way, what he has already been through would be horrific for him, poor little man.