Hiya, Kelsey! Thanks for visiting planDisney with your question.
Bibbidi Bobbidi Boutique (BBB) has many packages to choose from, some include a full ball gown and some offer a fancy t-shirt and accessories. My little girl recently enjoyed a makeover at BBB just a couple of months ago, and we brought her favorite princess dress with us. So, yes, Kelsey! You are welcome to bring costumes from home for your children to wear. I recommend having them dress ahead of time, or asking a Fairy Godmother’s Apprentice to use the changing room once you're at Bibbidi Bobbidi Boutique so that they will be ball-ready as soon as their makeovers are complete. (It can be hard to change after hair and makeup are done!)
Kelsey, while you're at
Magic Kingdom Park, I highly recommend using
Disney PhotoPass to commemorate your girls' magical makeovers. There are usually several PhotoPass photographers near Cinderella Castle and I think it is the perfect backdrop for some royal photos! Tip: Purchasing
Memory Maker in advance offers a discount on the
Walt Disney World Resort vacation photos from your entire trip!
I hope this information helps, Kelsey.
I'm happy to wave my magic wand and answer any other planning questions you may have!
Magically yours,
Melissa