The problem with "true" zoanthid IDs is that there is no standard reference for such things. The names are made up, sometimes on the spot, or taken from other strains to make them sound expensive. Just a simple google search of "white zombie" yields several completely different color morphs. It's honestly no different than renaming a dog you adopted.
It's also entirely possible the lighting is just different or that they lost color due to stress. The seller might have edited photos to make the color pop more than it does IRL.