Well said WinterLeia.
I don't think the three badly injured hikers could have been moved from the tent , if that were where the injuries happened. The remaining 5 hikers would not be able to carry or support them down the slope or would have had to make several trips at the very least which would have left very different tracks, they also would have collected more belongings/ equipment . Even the approach to the ceder and the ravine seems difficult in deep snow for a person that is not injured having looked at the many recent videos, without skis they seem to sink into the snow , with two of them with severity of the rib fractures, I don't think it would be possible.
Back to outsiders , for me , it's a strange way to try and kill people, if it was to be murder, to look like an accident, I would say it's an odd way to go about it. So much of the tongue was missing that it is also seems unlikely that outsiders or any person for that matter did that. To cut the tip off, perhaps possible if it was to be symbolic, I think so much of the tongue was missing that someone would have needed a dentist chair , a light and scalpel. In the cold and possibly at night, someone manages to do all this without cutting cheeks or leaving knife marks on the lower jaw would be a rare skill.
My thoughts for outsiders is only as far as the reason for leaving the tent , perhaps they were just threatened to leave and that was the end of any input, the rest was just the cold, falling into the ravine , snow cave collapse or falling off the tree on to each other., Perhaps even teddy's tree plays a part, the hikers climbed that ceder too and it collapsed/fell at that moment in time when gathering branches. It is reported that branches from the/a ceder were several meters away.