I don't know her canon (and she's the only one of your characters I've really interacted with a-aha...) but Azula is not only consistently characterized, but fun to poke with sharp sticks interact with as well. I think you're doing a good job with her!

... that counts as substance, right?

And Lisa is friggin' hilarious, just so you know. Especially with her interactions with Ran, Bender and Hancock.