If I worked the date out correctly (Rozemyne is 12 right now, Tuuli is two years older than Rozemyne, making her 14, which means she'll reach 15 this summer) , Tuuli should be part of the upcoming coming-of-age ceremony, so Rozemyne will have her work cut out for her to not accidentally deliver a mega blessing. ^^ Since it's still spring, I don't know if it'll be in the upcoming pre-pub part, but it will most likely be in this volume at some point.
With Trombe paper coming from a mana-sucking feybeast, their experiments might tap into that characteristic of the plant and inadvertadly create some new way to seal or steal mana. Imagine a contraption that has pieces of specially treated trombe paper suspended in a liquid that becomes adhesive when exposed to air. When it hits a target, the outer shell breaks up, glueing the trombe paper to the target, which then merrily sucks mana out. That'd be a nice addition to Judithe's arsenal.