OK, let me see. I know with 99% certainty that they will not push tables together at Crystal Palace or Chef Mickey's because of the characters. They have to be able to get around. There should be no problem at Donald's as I saw a huge group of kids there in March all at one big table. Now, Rainforest might, but I didn't see any large groups there. I don't think Prime Time has any big tables, big enough for 13, but I might be mistaken, all I remember are the booths. It seems to me last time I was at Mama Melrose's, there was a large group there and they were split into 2 tables, Biergarten has big tables, but I think they only seat 8 so that would be 2, probably right near eachother as long as it isn't packed when you arrive and I don't know anything about WCC as I haven't eaten there yet.
They will do what they can to accomodate you. Just be prepared and hope for the best. Make your request when you arrive at the podium. Obviously,they will see that the ADR is for 13 people so they will do what they can. There are just some restaurants that can't accomodate 13 people at one table or even right next to eachother depending when you get there. You will still have a wonderful time!!