Hi Shauna, and welcome to the E-Learning Heroes Community! So glad you're here! 🥳
Thanks so much for reaching out and sharing your .story file with us!
For your first question, I'd like to share a workaround that one of our amazing Heroes, Judy, shared in a different E-Learning Heroes Community post. She explains some navigation changes you can make in order to bypass that X button by utilizing a different design. Perhaps this could work well for your project!
To answer your second question, there isn't a way to change the size of a single Lightbox from within Storyline 360, but I’m sure one of our talented community members will have suggestions for you for any custom solutions that they've come across.
If any other questions come up, please let us know!