The character of Tulip is actually better so far than the book... much tougher. The actress just turns up the heat. I see the Malkovich thing in Quincannon; I can't stand Malkovich. Quicannon's grating of your nerves is perfect then, it's his character to a tee. Jesse is a much bigger "Bad Ass" on the show.
What I see is Tulip and Cassidy as Jesse's carnal sins made visible. His wrath, his lust, his gluttony, and greed; these side characters represent a sin or two in a way and Jesse is trying to save them as much as himself. I'll give it til the end of this season but I will finish the novels.