Tiana seems like a uber morning person...when they were frogs she was up bright and early and aleady had a raft made....the only reason she was tired in that picture was that she had just come home from working third shift as a waitress (which is exhausting work) and only had a minute sleep before getting up for her first shift waitress job...and heck she was a whole lot more cheerful there then I would have been on NO sleep...so I would say she is defiantly a morning person...
I was just guessing on Mulan.....

Or Ariel.

And Jasmine. We saw Mulan sucked with mornings in the movie, Jasmine just seems the type. I agree with SweetPea2007, Tiana's totally a morning person.

I see Mulan because she didn't like getting up at camp and she seemed like she was up late for preparing to meet the matchmaker.