My DD had a very wide fat foot when she was a baby and toddler. She could not wear Stride Rite either. If they found a pair that fit the front of her foot, she walked right out of them because her heel was not as wide as the front of her foot. Pedipeds shoes were about the only things she could fit into. They were fantastic. I would highly recommend them. If there is not a store that carries them in your area, they have a website.
I would assume at 11 months now, there is a good chance they will start walking before your trip and once they start, in my experience, they want down on the ground to do it. I wouldn't put a babies bare feet on the dirty Disney ground, plus if it is a warm day, that pavement could also be hot.
That wide fat foot results in buying expensive shoes for about the first 5 years! Even once DD was past the baby stage, she could only wear shoes that came in a wide, and never Stride Rite, so it was always the high dollar shoes for her, as most cheaper brands do not come in wide, or even in the unlikely event they did, they did not fit right. If it makes you feel better, around age 5 or maybe a little after, her foot slimmed down to where she can wear regular shoes. Since then, if she has seen a pair of shoes at Target she likes, chances are she will fit into them!