I have no idea. That's an issue for the lawyers. I do find it somewhat puzzling that CBS Licensing is willing to license the films to IDW Publishing but not to Pocket Books.
If it were solely up to them, CBS would be perfectly willing. That's why we got the go-ahead to do tie-ins in the first place, before they were cancelled. But it's also up to Bad Robot, and they'd apparently rather work with comics and games than with novels. As I understand it, BR likes to maintain in-house creative control over all its tie-ins, and they find that more feasible with comics and games.