Wow this one is tough!
Ok here are my thoughts:
An ability gained, an ability lost-I'm gonna have to say that its petrie, he learns how to fly in the 1st movie, but loses his bravery (1st movie he risks his life to save ducky, but in later films, like lbt 9, hes too scared to cross the canyon to tell the grown ups that they've been separated).
Fight fire with fire-This i guess would have to be spike. Not being able to speak or communicate that well to the other gang members. The only way he can help out is by physical strength.
Fear lies within- This would be cera. Though she tries to act tough and not afraid but really she is (in the tv episode "the spooky nighttime adventure" she acts like shes not afraid of the hidden runner and she hasn't had sleep stories when she really was.
Stir up trouble, let it grow-Believe it or not, i think its ducky becuase she can be very gulible, like in the 1st movie where cera goes the wrong way, and ducky follows cera becuase of her promise of her path being easier. Cera starts the problems, ducky can make it worse.
Innovation, key to the future- Littlefoot, he comes up with most all of the plans, like how to kill the sharptooth in the 1st film, or how to lead guido away from danger when he was sleep walking.