Two girls in some sort of forest reserve for magical creatures, one of them had a wolf-like companion?

[Bonnie]

This was a fantasy chapter book for children/pre-teens, and I believe it was a part of a series. I remember there were two young (pre)teenage girls (I think of the "opposites attract" variety, one was blonde and sunny and the other was sort of goth) who were friends and somehow found what I think was a kind of forest reserve for magical creatures? I think they got to become the caretakers. I remember definitely that there was a wolf-like creature that could maybe turn into mist, that had a name like Storm or Mist that was the companion to one of the girls. The copy I had was illustrated, and included a character/creature description section in the back. One of the illustrations I remember was this very fluffy magical creature that the girls were flying around on, with this small imp/fairy creature they had met. I feel like the illustrations were vaguely though not completely anime-esque. I would have read this in elementary school, so perhaps about 10 years ago. I don't think it was a supremely popular book.
Thank you so much!

[Bonnie]

Well, with a just slightly different word search on Google, I found it. Avalon: Web of Magic was the series, Circles in the Stream was the first novel I was thinking of, Rachel Roberts is the author. Can't believe I found it so easily just by tweaking my search. :D