I do like the way you think Miss Elizabeth. I have pretty much concluded that a second party was involved. They were attacked at the tent. The front door was blocked so cuts were made in the tent from the inside to escape. They were eventually subdued, but not without a fight. One of the party sustained very bad injuries and as they were marched down the hill the rest of the party had to help him walk. They were marched down side by side and near the treeline, the attackers (most possibly two of them and had firearms) proceed to beat them up one by one at the cedar tree with blunt objects.
Once the attackers KNEW that the party would not survive now, they left.
For what reason? I certainly don't know. Lots of speculation is running around out there. Maybe the attackers only wanted to get rid of one person and the others would have to be taken care of as to leave no witnesses.
I can only imagine the pure agony they all felt.
Thank you for your post Miss Elizabeth!