My thoughts as well, but maybe not. Perhaps Ceres is perfect because there IS water, but also plenty of rock to burrow into. I guess that would sorta make the whole point of ice haulers towing ice to Ceres moot though.
I didn’t consider the ice hauler part. That’s a further complication.
Then again, the protomolecule turned Ceres into a wasteland which then plunged into Venus, so I suppose it’s only complicated for the first two books.