I dont think, that the rav4 bodies were found in a very natural position as well. Anyway, we can presume, that the position of Kolevatov and Zolotoryov kinda makes sense (trying to warm each other). Nikolai was some 30cm downstream (probably been closer to the other two, but separated (naturally or not) at some point. Although, if they died together, or one after another in a reasonably short period of time, given the fact that they were very cold already and that bodies get stiff after death, it is strange, but anyway.
Dubinina is in the most awklard position. Probably her body was as well closer to the guys, but slipped away downstream to the position in which she was found. Her arms are pointing upwards, she is on her knees. Looks to me, as her body literally slipped, postmortem or in the best case she was nearly dead, with no strenght to move at all. According to the autopsy, everyone from the rav4 died as a result of "act of violence". I am wondering, what is the chance that they were murdered, or at least severely beaten, then left to die, and afterwards their bodies were just thrown on one another, piled up? Than it was a matter of exposure and nature for the decaying process.
As for the missing tongue, it is very odd, that in the autopsy report it is just mentioned as "absent". ("The tongue in the oral cavity is absent. The diaphragm of the mouth and tongue is absent.") She was in a strange possition, mouth open, therefore snow and melted water running through and generally a lot more exposed to elements than the others in the rav, but still strange to entirely lose the tongue, as it was never been there in the first place. In warmer conditions would make more sense, but with all the snow and freezing cold water... Or, the autopsy report is just presented in a clumsy way.
I dont know why, I keep recalling the Donnie Eichar`s Dead mountain, where he is describing the character of Liuda, and he mentions that it is known that sometimes when irritated, she would show untamed tongue behaviour, IIRC. If true, what a sad irony.