Erk! I'll get back to reading. Life caught up with me and I haven't got past chapter 10 on the second read! o_O
Regarding the fey: They are not so much rectal orfices as they are different from us. They are creatures of the First World, and as such they are wild, unpredictable, and follow a unique set of morals. In Occult Mysteries, they mention some stuff about the Gnomes in the First World.
So for the Fey, locking someone in a cage for a few hours and humiliating them is all in good fun. They don't really have consequences for their actions. If they played a prank and a human died and did not get back up, they would be like my two-year-old who wonders why they caterpiller she picked up (Squish!) doesn't move any more, or like Number 5 in Short Circuit who asks Stephanie to reassemble the grasshopper that he accidently squished.
As far as the Sprites' treatment of Jarrad, I think of them as a little brother (like I was many many moons ago) who show their love for an older sibling by playing jokes on them and generally trying to annoy them. Yes, Jarrad ended up thigh-deep in a Sprite Bog, but Nelsa (who IS awesome) points out that they are showing him where to find Sprite Bogs so he can use the mud to cure Poison Ivy, I mean, Fireweed!
Also, think of the Nixies who are basically GIVING Silverlake a constant supply of firewood.
What I'm interested to see is if/how Jarrad grows as a Wizard and how Serrana grows as a result of seeing her mother's interaction with Pine Callum. I don't think that Pine Callum is gone for good (for the record, my recollection of this story from my first read is pretty hazy).