I am in Ontario and we hear of sightings all the time . All the links didn't work for me i guess the page has closed but if people were somewhat close you you can throw the mountian lion , cougar ,bob cat even a black bear none of them can kill in an instant and if he she or them were attacked you woulda been able to hear them scream. I would love to see a documentry on this case even pics and what wittnesses had said thicase sounds very interesting..
The article I read about the return of the cougar to its former eastern ranges did mention possible sightings in Ontario as well as Minnesota but stated that these had not been confirmed, meaning there was no physical evidence. In Quebec 3 different cougars believed to be part of the same family unit were photographed and filmed on several occasions, analysis of tracks and droppings later confirmed the species. This was in the western part of the province, not in the Appalachian range located in the east.
According to zoologists it is doubtful that the cougar will ever be able to re-established itself in the eastern mountains due to the arrival of a massive number of eastern coyotes in that area since the 1940's. Unlike the smaller western coyote the eastern variant is bigger and goes after large prey, having in effect replaced both the cougar and the timber wolf as the apex predator in the east. Current numbers of coyotes far exceed any historical wolf population, there is simply no room left for the cougar. The other apex predator, the black bear, does not go after the same prey as the coyote and thus is little affected by the competition.
Which begs the question. Could a single coyote attack and kill a human? Absolutely. Is it likely? No. Would it be swift and quiet? Not likely, it would be like a dog attack except for the lack of barking. Coyotes don't bark but they growl and howl and this would be noticed.
Like you I don't think a wild cat (lynx) would approach a human, let alone attack one. We're talking 20lb cat here.
The black bear is responsible for the huge majority of fatal attacks on humans in the northeast and eastern Canada. Due to its strength it can kill with a single blow and it is physically possible for one to attack without leaving the victim enough time to scream. But it would leave plenty of evidence of what had happened and in these cases none was found.
I am strongly inclined to think that the disappeared were the victim of accidents rather than a predator, be it human or animal. Mountainous, wooded areas are treacherous, wander off the beaten path and you may quickly find yourself in serious trouble. You could fall off a hidden cliff, fall into water and drown, be struck by falling rocks, or get lost and perish of exposure especially if no one knows where to look for you. Your body may not be found for years, if ever.