Hamsters are fine. Aquarium pumps typically don't fail "all at once", they just suddenly become much weaker for a while before actually failing. I noticed the bubble stream from the habitat was greatly reduced, down to just a meager trickle of small bubbles every few seconds.
Here is the one I was using. It's expensive but the battery backup feature is a must, given that it's life-critical.
I actually don't have two land cages, so George and Scott will need to cohabitate while I build a second one. I could use some donations for that new pump if any of you are feeling flush. I could rush out and buy a cheap normal air pump from petco, but the specific features of this battery backup model are really necessary for a project of this nature.
EDIT: Nope, they began fighting immediately when placed together. Evidently I need to drop what I'm doing and build a second enclosure right this minute. Oh well.