Indeed if you provide me precise criteria I can rename easily batch of vehicles.
Either just based on model/name/body type, or with year ranges.

For "de Ville" vs "DeVille", no idea what is correct.
The original French word used in automobile world (not only Cadillac) was "coupé de ville" which means "city coupe", they derived their model names from there I suppose ("sedan de ville" has no meaning, nor has "de ville" alone, except being city-related)