Currently themes and custom CSS and JS do not export into Quizzes.Next, but clearly several elements from the main instance of Canvas do (the assignment descriptions, for example).
It seems wrong to allow admins to customize the user experience except in the quizzes and tests.
We wanted to have JS create a button by every question item, so students and tutors could easily click if they wanted to report an error. Unfortunately, the custom JS can't reach the LTI, and the questions don't have their Item # when students view them anyway.
It would also be nice to stamp quiz items with a trackable number.