The English fluent person they knew, Joaquim, wasn't at the reception but close by at the Tapas bar.
You don't seem to be aware of the state of a body after 10 hours.
So you think they would have said 'lets go and find Joaquim and explain to him what has happened and get him to ring the police''. What if he wasnt around at that time? Or would they automatically think that Reception was the place to go because they knew it was staffed with English speaking people?
Apols if I'm wrong but wasn't it you who said it would only take 3/4 mins for someone carrying a body to get from the complex to the place where Smithman was seen? So we must be talking far less time than that to run to Reception without being encumbered by the extra weight of a body.
Two doctors would know all about the changing states of dead bodies.
But what would it matter when apparently they knew a place to leave it where the biggest search ever conducted in the history of Portugal could not find it - not even the locals. And the state of the body was apparently not a problem when in the full glare of the worlds media - they removed it 3 weeks later to yet another unfindable place.
The whole concept that they would dispose of their childs body is nonsensical IMO- and even more so the idea that they chose the most complicated cover-up plan ever devised - when there was absolutely no need to - unless of course they were ALL complete idiots who didn't have a working braincell amongst them.
None of them remotely fits that description as far as I know.