1. Something scary enough to drive them away from the tent without adequate clothing or equipment
2. A careful decent of the slope which would be consistent with calmly walking away from a dangerous animal
3. Dropping the flash light and not stopping to retrieve it
4. The group heads for a tall cedar and climb the tree clearing branches to look back up the slope.
5. Yuri D receives scratches bruises climbing the tree his fingers and toes are severely frost bitten. It does not appear that he climbed the tree to collect firewood.
6. Fragments of skin found in the tree bark
7. Yuri D and Yuris K die of hypothermia. The fire is lit too late to save their lives.
Hmmmm.... I like your enthusiasm and theories Star-Man, but I think you may be reaching really far now. Literally everything you list is most definitely not 'evidence' contributed to Yeti or a "large primate" dropped on the pass for some super secret experiment.
Evidence in favor of what you propose would look more like.....
Yeti sleeping in their tent. <<. Roflmao
I think you get the idea. Everything you list and the injuries you allocate can be contributed to..... Anything. It can all be an indication of goblins, trolls, mothman, and unicorn farts if you really wanna go down that road.