Interesting speculation, but where would it have gotten the boost to "climb" all the way to Ceres?
the same way NASA spacecraft slingshot to Mars ,Jupiter, even Saturn. Venus and the sun..
"Slingshots" are carefully controlled maneuvers that must be executed at exactly the right time. They don't just happen. The bright spots on Ceres could be Snoopy, but I doubt it. I think the freshly-exposed-ice idea is more likely, but even then I don't believe it is ice.