Because their only appearances in the Vault were either in shadow or in range of the magnetic magic, their original color can only be seen in their Skystone. Their silver plating can be later seen in Imaginators, as they are in areas open to the sky.
In the Clutch artbook of Skylanders: SuperChargers, Cauldrone is revealed to be a scrapped core Magic Skylander, with a bouncy disposition. When they were made into an enemy, their pink and green eyes were replaced with malevolent black and red ones, and they no longer have their lid.
Because of Cauldrone's heart-shaped ornaments and large eyelashes, it is possible they were a female Skylander, but there is no text information on the character's development.