I agree with User45 that the publication of the photo of the unknown body could lead to a re-interpretation of the tragedy.
At first I thought the body couldn't be Alexander K's, but in part that's because I mistook the black body bag for his clothes. I think the striped shirt he's wearing in the frozen photo looks lighter just because of the snow crusted on it. The comparison photos people have posted have been really useful.
So here are what I think the repercussions of the new photo are, if it is indeed of Sasha K. I had always suspected the bodies in the creek had been laid there by the killers while the hikers were dead or dying. It's an old criminal trick to put bodies in water, especially flowing water, to disguise identities and to obscure clues--the Mafia, some gangs, and some serial killers of the "organized" modus operandi to it. (I'm a professor at a college of criminal justice, and although I'm not in law enforcement, I consult with with my colleagues). But you know who else does it? Police, the military, and intelligence--in short, people who work around criminals.
If Alexander K appears in the photo, it suggests that he was found in February and that the "II" in the case files wasn't an error. The authorities found them, with disfigured faces and eyes and tongue gouged out, and were told to cover up these injuries. They laid them in the stream bed, and when the stream started flowing more heavily, Alex K's arms shifted slightly. (I also think Semyon's camera was wrapped around his wrist, and that those covering up the scene might not have found it when they moved him since it was hanging inside his cuff). The pose he is in here suggests his wrists may have been bound. The others may have been dead in the snow den--it looks like a standard WWII-era snow shelter of the kind that was still taught in survival classes when I was a kid--or elsewhere.
Can anyone with a better visual sense match the background in the new photo with settings in the other shots? It resembles the area around the cedar to me, but snow and evergreen branches all start to look the same. And the question, of course, is who or what defaces people, gouging out their eyes and removing a tongue. The KGB or the military wouldn't knowingly and ritualistically disfigure the flower of Communist youth, with their technical knowledge and service to the state, so I think we would have to look elsewhere.