Anything is possible but...... That would mean they made 2 snow caves and they both collapsed.
That's True. I guess we are all trying to work it out. But the first place found with the flooring of clothes and branches didn't seem be a cave. We don't know what it was other than it had flooring and no bodies were found there.
The ravine 4 were found under the snow in what was a stream in the ravine. It might have been frozen at ground level, with the natural over hang of the snow drift. Call it a cave or shelter or whatever.
Other theories are they were put there on purpose having sustained injuries by, gun butts, Bigfoot, KGB , aliens etc.
Or.... They went in to a space formed by the snow. Maybe dug it out a little, chipping away at the edges. Lay down for body heat and shared jackets for warmth.
Then the roof collapsed. It would be a large instant mass falling that could explain the injuries. If the ground was hard Beneath them (not more snow) it could explain the rib fractures , neck deformation etc.
I know it's frustrating.....but it's reasonable possibility and fits without too much complication.
If they weren't crushed by snow then I don't know of another suggestion. Others might.