The movie has a heartfelt message about love being the most important thing of all, trumping both financial and professional success. And Tiana is one of the only Disney princesses who doesn't have to be rescued by a man. The movie's secondary voodoo theme, while tongue-in-cheek, plays to assumptions of what New Orleans is like.
A scary villain (who commands very creepy shadow minions and casts voodoo spells involving the "other side") and some cartoonish battling: For example, a man clubs another with a piece of wood, and inept hunters brandish guns and clubs at each other. One throws knives at Frog Tiana. Also, the villain hurts a major character badly. The injury leads to death, which is gracefully handled -- though still pretty intense for a kid-targeted movie.
Characters kiss when they live happily ever after. The plot turns on a princess kissing a frog. Naveen is quite the ladies' man, but it's mostly shown through very mild flirting.
Tiana is a Disney Princess, whose brand reaches far and wide. Expect to see Princess branding on consumer merchandise, food products, etc. as well as in books, websites, and other media.
Drinking, Drugs & Smoking
Some adult characters hold and/or sip from wine glasses and champagne flutes at restaurants and parties.