Be aware-- The fourth book in the series was written and published first. It kind of constrained events in books 1-3. Book 4 got rewritten after the other three came out, but I think it was more to smooth out the prose and characterization than it was to change anything major about the plot (haven't done a point for point comparison).

Book two has a different (male) POV character. Cimorene is in it, eventually, but isn't in the first couple of chapters.