I have been thinking about all the rides and logistics of potty breaks etc. I do have a double stroller (pram) and my 2yr old and baby will be riding in it. I also have a sling that I can carry the little one in.
When we went in Feb, my husband carried the baby in the snugli and most rides they counted him as 1 person. I don't think DDs are brave enough to do rides on their own. I guess, since we visit DLP all the time, it's not all about the rides. So, if they give me a hassle, DD4 will have to sit alone or we just have to skip that ride.

Besides, the only ride they want to go on over and over and over again is it's a small world
As for the bathroom situation, I deal with it everyday! So no big hassle there.