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 Wee Free Men
Fridge Brilliance: Tiffany mentions she once had her fortune read at a fair and was told many, many men would want to marry her — in the next chapter she learns that being kelda means she has to choose a Feegle to marry.
Nightmare Fuel: Ooh, lots. Take the Dromes, monsters that look like humanoids made of dough which kill people by trapping them in dreams...
We also find out that they aren't even native to fairyland, the Queen found them useful so she essentially kidnapped and enslaved the entire race. One that finds itself in a dream it likes immediately stops being hostile, suggesting they are driven by raw terror at their surroundings as much as anything.