As the book progresses, you might notice some overlapping techniques. Some Rooting Interest Techniques are also Character Deepening Techniques. For instance, Spengler, the man with the Mask of cynicism, may have Rooting Interest because we learn of his pain but pain is also NPC Deepening Technique. So is self-sacrifice, which he does when he attacks the dragon.
Not every NPC Deepening Technique (an NPC exhibiting insight, for example) is a Rooting Interest Technique. And not every Rooting Interest Technique (an NPC being genuine, for instance) is a Character Deepening Technique. But some of these techniques do overlap.