If authorities say Gus isn't on the property, then he's off the property. The question then becomes, how did he get off the property?
A 4 year old can walk how fast, and how far? It's a guess, but 3 or 4 kph maybe. And then the question for me is, would a 4 year old hold that pace for an hour before sitting down, would he/she walk steady for 3 or 4 hours in a straight line, placing the toddler 12 to 16 kilometers from the start point?
Then there's the raptor, that eagle hawk. Well, I doubt that bird picked Gus up, the young lad would be simply too heavy.
Dingos? No sign of that, no drag marks, nothing reported on that as far as I can see.
So, if this boy wasn't 'disappeared' at a time earlier than reported, and he wasn't kidnapped, and he wasn't taken somewhere by someone, and he didn't walk away, then my only conclusion is, he's somewhere near the point of his disappearance. I've read numerous accounts of searches that totally missed the persons being sought, eventually to be found close by.