This is quite the plot twist you've unleashed on us with these developments! You really set us up to believe Talbot was going to be the wolf, and it worked! I didn't suspect it was Jen until they opened her book. :3
I'm a little curious though because I thought the critters had to murder and/or cannibalize BEFORE going beast-mode? But Jen did it AFTER she started to turn, according to this... guess I misunderstood something ^^;
(PS: How come Wolfy's face is all bloody? Was it the fight with the rats?)
What it takes to start becoming a Therian is still a mystery that will be explored and unraveled throughout this series. Whatever critters might say about this curse are mostly speculations and should be taken with a grain of salt. And the blood is from the many rats killed and devoured.