The thing is that the main story line is going to stay the same. Therefore, ideas that divert too hard from it are contraindicated.
Or even shift the balance of power. Developing a subplot about trying to break the curse on the secondary character is sometimes unwise. Though she might get caught in the part where wizards try to use her to get to the position where they could try. (It never works because the curse is plot-crucial.)
The queen is going to be annoying. Especially after she learns that her niece might be able to help her daughter.