The do's and don'ts of interacting with the characters during meals are much like those during other character greeting experiences, plus a few more. You can look
HERE to find a video I made with my family about tips for meeting characters.
1. Have your autograph books ready. If you're asking for a character's autograph, have the book open to a blank page. Also, make sure you have a pen with you (a pen with a fat barrel works best) and then the pen caps is off.
2. Have your camera equipment ready. As you see the character approaching take the lens cap off, turn the camera on.
3. Wait your turn. The characters really will get to every table, watch for a moment and you'll the direction they're traveling. It can be tough for kids to wait, but keep your children at your own table until the character approaches. Other families don't want your kids in their picture.
4. Have your kids at the table when the characters are on the way. This can sometimes be a challenge at a buffet. Pooh is on his way over, but your child needs another waffle. Better to stay at the table and get the waffle later than miss the character.
5. If you do miss a character, ask the character-handler for assistance. Usually, these are cast members nearby wearing some sort of headset and often a yellow vest. They will help you find the most appropriate time to squeeze into the rotation for a quick "goodbye" photo. Don't upset the character or other guests by cutting the line.
6. Seat children together on the outside of the table. The WDW restaurant servers almost always suggest this. It makes for MUCH faster photo posing.
7. If you're taking video, be aware of the time. Other guests are waiting too.
Most of this is just common sense. Be courteous and aware that all the other guests want the same thing you do and you'll be just fine. Have a great trip!