Hikari has only been tagged with fox_tail once before and fox_ears three times before, though two of those times there were other characters that are a better fit. I do not think that her tail or ears are fox type. For now I'm changing the tags to tail and animal_ears.

The only other post where she's tagged to have fox tail and ears is post #2546494, but that post has parent and sibling posts where she's simply tagged with animal ears.

post #2577513 has her tagged with squirrel_tail and squirrel_ears. While I don't think her tail looks like a squirrel tail, the squirrel on her arm in post #3000540 seems to support this. If I'm not mistaken that is official art and the witches are sometimes depicted with their familiars. There are however only 16 pictures where she's tagged with squirrel tail or ears.

The World Witches wikia says that her familiar type is "Fuso Squirrel" ("Fuso" being the name of Japan in the World Witches universe), so I guess that settles it.