There is one thing I noticed in seeing the multiple views of Ceres which show the bright spots rotating toward the dark-side terminator. That is that the spots maintained brightness regardless of their angle toward the sun. (I disagree with Ms. Howe on whether they stayed bright past the sunlit zone. There wasn't really a good image showing that.)

That the brightness was unchanged by the angle of the sun indicates that the bright spots were not due to reflection from a flat surface, such as a sheet of ice. That would only reflect when the sun, the ice, and the spacecraft were at just the perfect angle.

The most sexy hypothesis I came up with was that the spots could be reflections from huge glass-like domes, which would continue to reflect the sun from a wide range of angles. Such domes could of course be the product of an alien civilization, either current or long vanished, or could be bases of the rumored "breakaway" human civilization of the elites using secret technology.

The other, less buzzworthy theory I thought of is that the spots might be large regions of hoarfrost-like ice deposits, which would be pure white from any angle. Such deposits might occur in the bottom of a crater if the impact broke through to a subterranean ice layer, from which ice crystal hoarfrost might form large outcroppings due to sublimation.