For now, the Question Types feature isn't related to preferences. At a later stage, it will be possible to deactivate certain question types here.
What is already available there is an overview of the available question types (animations that explain the concept of each).
Sound & Music
Music is played before a question comes up. Sounds mostly give feedback, such as to a correct or incorrect answer (or a correct or incorrect part of an answer).
This is unrelated to Quizcover's built-in video player that is part of the Solution Display. The feature you can activate in the Gameplay Preferences is an iOS system-level feature. The recordings are stored on your device (separately from Quizcover).
For details on this feature (which gives you free access to one booster per question), check out the related page.