These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: The Tomorrow Series
Author On Board: Marsden becomes a lot more overt in the Ellie Chronicles in using his characters as mouthpieces for political and philosophical ideas, and there are lots of references to (ie recommendations of) books and poems.
Canon Sue: Some sources point to the fact that Robin is the most explicitly based on a real person and has a touch of being "too nice", with her flaws being largely informed rather than shown.