Thanks, ReggieB and mitros!!!
There are a bunch of non-signing characters out there wandering about Disney World! King Louie, Mike, Sully, Goliath the Lion, Carnataurus, Conniesaurus, Figment, Nemo (obviously!), and Bullseye never sign since their poor hands really can't hold a pen! Some obscure characters don't sign, like Goliath the Gargoyle, Walrus, Dumbo, Rolie Polie Olie, and Zowie. Stamping character include Mr. Incredible, Mrs. Incredible, Frozone, Kermit, Miss Piggy, and Buzz. Woody stamps at MGM but seems to sign at MK. Some characters are hit-or-miss if they will sign, like Mr. Penguin and Beast. Some characters have others sign for them, like Belle may sign for Beast, and maybe Jessie or Woody will sign for Bullseye (but I am not sure about that!). Whew! That was probably more info that you ever wanted to know!
On our website, we list everywhere we seen the characters, and other places we heard they can be found. We are missing a few really rare characters (like Jane Porter, Brer Fox, Shang) but hopefully someday we will get them!! The actual best times to meet characters are very dependent on location. I personally find character-hunting best in the morning until early afternoon. The worst times to look for characters are the hour before/after the mid afternoon parades! Many (but not all) characters stop meeting then to go get ready for the parade. I usually head back to my room in the mid afternoon since there are hardly any characters out and I have no one to look for! And checking the Times Guide is always a great idea!
Hope you find all you are looking for!!!!!!!!
aw:
Maybe you should ask your DD what she would like though. 
