This was very interesting and different! My friend and I made a themed list of odd jobs in HP fics a couple of years ago. It began from a quote that said, among other things, "imagine that Snape joins a travelling circus..." :) But there hasn't been a fic like that on the list until now! Whee :)
The imagery and the magic in your story was so fresh and unusual!
The was one thing that jolted me: when you first switch POV to the snakes, one of them, after speaking about sex in "snake terms", suddenly says something about pheromones. Was a POV disruption, IMO.