Here are some photos I took of other visitors (none are Disneyland staff). The most popular costume was Alice in Wonderland.
An important part of cosplay seems to be posing and taking pictures of each other. Here are 2 Alices are taking photos of a Peter Pan and Wendy.
A panorama of Alices in front of Disneyland Castle.
Some Rococo Lolitas - we often see this style in Harajuku