The Queen began life in the novel as someone aware Eileen is actually better at magic than she is (and not liking that much). The Queen takes off as a character in my view when she allows Eileen to defect, stunning Eileen, who thought she was just going to be booted out, and horrifying Brankaresh who thought with Eileen's defection that was the end to one troublesome fairy godmother (either by execution for treason, his preferred option, or by just having nothing to do with the magical world ever again and having to make do with life on Earth). The Queen's stubbornness here encouraged me as it confirmed the familial traits she shares with Eileen. I think also at this point where the Queen is being manipulative the novel really takes off and Eileen is aware the monarch is going to do her level best to better Eileen.
Jenny, to begin with, is a whinger (though given her mother's tale and the consequences it is understandable) but she too takes off as a character when she stands up to Eileen and the Queen. At that point I feel sorry for Eileen, beleaguered by both sides but I believe if you really want to know what your characters are really like, put them through absolute hell and see how they react.