Neither Tinker Bell nor Peter Pan are currently regularly scheduled at any character meal. However, you won't have much trouble getting some face time with Tink and Peter.
Tinker Bell has a regular character greeting area in Pixie Hollow in Toontown in the Magic Kingdom. You can meet Tink and several of her fairy friends every day. Be sure to check the free Times Guide when you enter the park to see exactly when the fairies will be available. If you're at the Magic Kingdom during the Wishes fireworks show, you may also be able to get a glimpse of Tink in the sky.
Peter Pan can sometimes be found at the meals at Cinderella's Royal Table, but this is rare and not guaranteed, so I really wouldn't count on it as a means of meeting Peter. However, Peter Pan can often be found greeting guests near the Pirates of the Caribbean ride at the Magic Kingdom.
My personal best Peter Pan experience occurred on the Family Magic Tour of the Magic Kingdom. You can read more about this
HERE.
If you need more information about how to find your favorite characters, the best way to find this would be to go to
the guest relations office at any of the theme parks. Ask them to call
the "character hotline." They will be able to tell you if, where, and
when any particular character will be appearing on WDW property.
Enjoy your stay at Walt Disney World.