Hi Eileen - sorry, I meant to edit my comment but ended up deleting it and your reply by accident!
I'm pleased to hear the changes have worked and this demo is now more inclusive. If I'm honest, it was a tricky fix and I am still working on some glitches*. But it was the right thing to do and I am grateful you pointed this out.
Once I have tidied up my master file, I will share it here and also post a blog detailing my process. TL;DR if I had considered this from the start it would have been much more straightforward. Which underlines the importance of always designing for accessibility, even in rapid prototypes such as this one.
*
https://community.articulate.com/discussions/articulate-storyline/issues-retrofitting-accessibility-functions-to-a-former-drag-and-drop-exercise