This last chapter has raised a couple of questions that I hope are eventually answered. Seeing as how Vivenna can invest her breath in the shawl to keep it safe, is it possible for her to invest only a small portion? For example, could she get multiple small wooden dolls and invest them with 1 breath each? Taking this a step further, could she then give away the breaths one at a time, pulling the breath out of the next doll to do so? The reason I ask, is because Vivenna is a smart girl, but (like your readers) doesn't know everything about BioChroma, and since she had previously desired to give the breaths to drabs, it is something she might think about. If it isn't possible, why not?
Also, have you explored the possiblity of underground slave markets? The selling of children for their breaths? I recognize this is a more light hearted book, however, in such a society where breaths are a valuable "currency", there are always those who will take advantage of the weak willed and gullible. "Orphanages" that raise children until the point where they can say those vital words, and stealing their breath, or selling the child to the highest bidder for their breath. (That way the orphanage is not responsible for what happens to the child after its sold.) Vivenna is in the perfect position to stumble across a black market like this if one exists.