Hello there, Stella, and welcome to planDisney!
I absolutely LOVE your idea of changing into a couple of new Disney Bounding outfits throughout the day! It always amazes me when I see guests Disney Bounding in the Parks. The detail and thought they put into their outfits are truly impressive!
Disney maintains an
FAQ and a list of
prohibited items that will not be allowed through the security checkpoints as you enter the Downtown Disney District. I'm afraid that suitcases with wheels are listed under prohibited items, as well as suitcases larger than 24" long x 15" wide x 18" high (61 cm x 38 cm x 46 cm). If you can find a large backpack that is within compliance, Disneyland Park and Disney California Adventure provide
lockers which you can rent for the day to store your outfits.
With Halloween approaching, my fellow planDisney panelists recently gave
advice on costumes and Disney Bounding. You can even see a picture of yours truly with my family when we visited for Oogie Boogie Bash! You sound like you have quite a plan for your outfits and I bet that you're going to look fabulous. Don't forget to commemorate your visit by taking advantage of Disney's PhotoPass photographers, especially with each outfit change!
Stella, I hope that response was helpful for you and that you have a wonderful visit to the Happiest Place on Earth! It's such a welcoming place for everyone and I love seeing people showing their love of Disney in so many various ways, including Disney Bounding!
Have a Magical Day!
-Al