I can see bits of many of the types, but in the end I'm leaning towards Thief as well. They're among the most cheerful, and they're more likely to be leaders than some of the other types. All six of the adjectives you picked fit well in a general sense with most of the thieves in the series, and there are some of them that can be cautious yet still do things on a whim, such as Locke and many of the ninjas counted in the category... and I guess even Balthier could fit in that category since a pirate isn't too far from a thief. Your sense of humor also reminds me of that class, as odd as that may sound.