Though still a long way off from completion, my own pack contains rating names that are somewhat associated with foxes (since I'm known as the Curious Kit nowadays), and happen to begin with C - that is:
Cute
Curious
Cunning
Chaos
Challenge
Chaos is a synonym for Mayhem and Havoc that I've wanted to use for ages, while Challenge contains Original and Oh No! levels with more limited toolsets or tighter requirements.
For the Original Lemmings, the rating names, at least the first three, seem to be adjectives based on the general feel of the levels (i.e. "That's Fun"... "Hmm... that's Tricky"). For Oh No! More Lemmings, the ratings are slightly based on the friendliness of animals in the eyes of humans (i.e. "A Tame Animal", "A Crazy Animal", "A Wild Animal") - of course, Wicked is stretching it, and Havoc just seems to be a synonym for Mayhem.
My suggestion would be to find a theme, no matter how random it might be, and come up with a list of adjectives that fit it and build from there.