Thats kind of the point. They should all have multiple injuries..
That's just not the way these incidents work in reality. There are always things that seem inconsistent but can be explained if enough resources (including reconstructions) are done, but the investigators have to possess an imagination, for example, it may be that one or two of the "ravine 4" were being carried when then fell onto the rocky creek, though I don't think this is necessary, since there were plenty of possible injuries that could have occurred even before they even started back to the "den" and until a good reconstruction is done, it's all speculative. Therefore, a good investigator tries to put forth the most reasonable hypothesis. Then it needs to be tested.