Cool news. I might check out the Walter/William/Nina book.
Has anyone read any of Christa Faust's work before?
Yes. She used to be a rather prolific horror writer, alongsize Poppy Z. Brite, before she got into the tie-in line. The most recent of her works I've read was the Snakes on a Plane novelization, which stayed true to the spirit of the movie but was far more entertaining.
I wouldn't hesitate, if you're already a fan of Fringe. She'll do just fine.