I have absolutely no idea if DD3 will like characters or not because she is pretty shy. I’m torn about if I should include characters in our TP or leave them out.
We are doing a couple character meals (Chef Mickey’s, Crystal Palace, and Akershus).
Do you visit the classic characters at each park? Or just one?
See how she does at the character meals… then adjust plans after that. You should get most of the major characters at the meals you have planned.
I’ll never forget the look on my daughters face (3yrs old) when she encountered Chip & Dale in front of The Land in Epcot. It was hands down the best part of that trip! To me that’s what the magic is all about! I would plan on characters, and change if you find it’s not working for your daughter.
Have fun!!
When we had MM I really appreciated the M&G with my littles. They were shy but they got more used to it throughout the week. I like to do 2 M&G per day. Don’t miss talking Mickey. 
I agree with @lauretanoDW2014, see how she does at the character meals. My DD turned 3 in the parks, and she was wild about Winnie the Pooh and his friends.
When my daughter was three, Chip and Dale were her favorites! We had to get in their line EVERY time we saw one, in EVERY park!! She even knew by the end to go up to the handler and ask if the line was still “open” or not before we got into it. I agree, it was the best part of that trip.
I agree with what others have said that you should include them in your Touring Plan and if she hates them, then you can easily fill in with something else on the fly. The thing about character meets is that they are hard to add in after the fact because they have limited FP+ and many don’t even offer it.
My one regret with my DS1 is that we didn’t plan very many character meets. Everyone had warned me that he would probably be afraid at that age so I didn’t plan any beyond a Tusker House breakfast. Well color me shocked when he became obsessed with Mickey and Minnie. We snagged a last minute FP+ for Mickey and Minnie later at AK but of course he fell asleep just prior to it and I didn’t get a very friendly CM later when I went back after it expired. We lucked out at the Epcot Visa meet at the last minute thankfully! Even today he points to these pictures on our wall and says Minnie and doggie!
We took my DD at age 3 to DL. I was worried too because things around town, like the characters, kinda scared her. When we met Mickey it was love at first sight from them on. I will say it was a little weird because she loved watching Sophia and Doc McStuffins on TV, but she did not like them, at all, as characters. So the human cartoon characters with the big heads, NO! Disney Animal Characters, yes! Of course Disney Princesses, giant YES!
I would add some specific character meets in for characters that you think she might like, or that she has seen in movies already. Even if you aren’t sure if she’ll be too shy, from what I read, the characters work really hard to draw kids out of their shells. If you think it could be an issue, you could always tell her “We’re going to get some autographs from Rapunzel today in your book, and then when we go home, you can show them to Mr. Bunny (or whatever stuffed animal she loves is at home)”. That way it makes the meet less about her smiling or posing, and more about your daughter getting autographs to show to her ‘friends’ who are back at home.
Thank you for all the input! I’m going to plan out some m&g time into each day. She’s a pretty shy, socially anxious kid so I don’t want to make her uncomfortable. But I’d hate to not allow time & her ending up loving the characters! I’ve never planned a trip with young kids before, so it’s new territory for me.
When we went to DL recently, I was with a super shy 4y old that did not speak English. However, she LOVED every character, to the point she kissed Eeyore on the nose and did not want to leave Olaf. But she took three days to talk to me (and I speak her language). I think that the magic of Disney really brings something in the kids.
Winnie the Pooh and his friends tend to be small and fluffy and cute, so that could be a good start. Chewbacca, Darth Vader are HUGE (my 6.4 tall boyfriend is still much shorter than Chewbacca) so I would stay away from them.
Pooh and friends are all a lot taller than me! I think Mickey/Minnie and Tink are the smallest.