In a blizzard water is going to be the least of your problems.
Just put a garbage bag in a container and let a load of snow melt inside it.
You are not going to be resorting to cannibalism either, as romantic as it might seem at first.

Keeping people from getting to bored for the few days it takes to dig out is the big one. Keeping them from feeling hungry is the second one. Honest.

The scenario posted has enough people in it that even if they had no clothing at all they could stay warm just by huddling and sleeping in a pile.
Something for mattress padding would add to comfort though. How much shredded paper did you say there was?

Dealing with sanitation might be something to think about, but there will be plenty of paper shreds, waste baskets and garbage bags if the toilets are not working.