Characters can always be found at the Good Times Gathering Spot when it is open. Usually these include (but not guaranteed or limited to) Chip, Dale, Koda, Kenai, Thumper and Miss Bunny. Pocahontas does appear throughout the day to tell stories, but not normally pose for photos. She has posed in the past, but not before or after storytelling - usually she appears randomly at other times. Meeko has been known to join her for storytelling, but is not always there.
The GTGS is also a good place for meeting random and/or rare Disney pals during the off peak seasons when performers are in training (typically late Jan/early Feb, late May/early June, and late Aug/early Sept). These in the past have included Launchpad and Marie, amongst others.
Please note that the GTGS normally only operates fully during peak seasons such as Summer and Christmas. The random and rare pals are only there occasionally during off peak times, and no storytelling normally takes place during this time.