Hi John!
Thanks for coming to see us at the Disney Parks Moms Panel. I love to get awesome souvenEARs during a Walt Disney World Resort vacation because it helps keep my magical vacation memories alive!
The best way to determine merchandise availability is the
Shop Disney Parks Mobile App. This app will allow you to search all of the merchandise available at the Disney Parks, along with merchandise availability. For some merchandise, you have the option to ship it directly to your home. Other merchandise will be identified as "In Store Only", in cases where it can only be purchased inside the Disney Parks. The app will also allow you to find the specific stores that carry the merchandise you are are looking for in the size you need based on each store's current inventory.
You can also check out the
Shop Disney webpage for Disney Parks merchandise that can be purchased online. This is a great way to find merchandise that can be shipped directly to you, but it won't show merchandise that can only be purchased in the parks. So if you have someone who can pick it up for you, then the Shop Disney Parks Mobile App will give you more options to choose from.
I just looked in the Shop Disney Parks Mobile App for both Space Mountain and Soarin' Around The World to view merchandise themed for both of those attractions and I was able to find multiple t-shirts that you can choose from. So hopefully, they will have the perfect shirt for your princess.
Let us know if you have additional questions! T-T-F-N, ta ta for now!
~Crystal