Hi Judy!
With a daughter who is "All-About-the-Disney-Princesses," we're always looking for a chance to catch a Princess, or any of the female characters, but Pocahontas is a tough character to find. I've been told she can be seen at various places at Animal Kingdom (near the entrance, by Camp Minnie-Mickey, etc.), but in all our visits we have yet to see her. Here's wishing you'll have better luck; Animal Kingdom should be the best place to find her.
The Princess Storybook meals at Akershus (Norway in Epcot) is the best place to see Ariel while eating. Disney princesses sometimes rotate, but we were fortunate to see and get pictures with Ariel at least our last 3 to 4 visits.
As for time in Animal Kingdom, if we started at 9am we could probably be done by 6pm with moderate crowds.
Have fun! If you do see Pocahontas, tell her a Panelist and his daughter have been trying to meet her
:-)