I have a couple thoughts on standard practices.
Regarding the question on stashing gear: it's quite common to stash gear such as approach shoes or skis, or gear you regard as overkill now that you're on the mountain and have suddenly become optimistic about a straightforward climb. Had a cache of bivouac gear and extra stove fuel been found it would have been a very negative sign. It hasn't. Hooray!
Snow caves: I've spent probably around 2 weeks in snow caves, trenches and igloos. As others have said, it's imperative that the top of the entrance be lower than the sleeping platform. That accomplished, it's up to your body heat to warm the place up. The larger the volume, the more energy your body will use heating the place, so unless you're quite comfortable and well supplied, try to find another way to alleviate your boredom. Apart from enlarging your cave, that is. And of course, you don't want to get your clothes any wetter than you have to. Finally, because your world is built out of water doesn't mean you have plenty to drink. For all practical purposes, you're limited by the amount of stove fuel you have. Yes, you _can_ catch drips, squeeze it from your clothing (yuck!), and melt snow with your body heat, but you can't stay ahead of dehydration.
I don't bring that up to discourage anyone - I'm optimistic that these well prepared climbers brought plenty of stove fuel. I just don't want anyone thinking they can count on eating snow for hydration. Oh, along those lines, when cooking and melting show in a cave, ventilate it! Carbon monoxide and all that.