I'm not seeing that much of a resemblance, as her hair is more blonde, while Holo's is brown. Besides, nothing on the pixiv page suggests any link, either (especially considering that the title describes her as a fox whereas Holo is a wolf).
reminds me on the episode when holo heard a story that yoitsu was destroyed from the bear who hunted the moon and become so desperate and say to lawrence: will you mate with me? if i become a child then two of my kind i will not be alone anymore! it´s seems he accepted her offer.
What do you mean, you're not seeing a resemblance just because they have different hair color? They have the same haircut, both have the locks of hair coming down in front on either side, both have red eyes, and both have white tipped tails. The only major differences are hair color and the styling of the ears. It's a very easy mistake to make.
But the reality is that, however much she may look like her, this is certainly not Horo.