And for the button location: edit the Master slides for Quiz (be sure to change all master slides for the type of questions you are using) if you haven't yet created the question slides.
If you have already created the slides: the Transform accordion has a small curved arrow top right that can be used to apply changes to one button to all buttons with the same style. Since the quiz buttons all have their own style you can use this arrow for each button separately. Although all quiz buttons use the same button style, you can choose either "Apply.... same type" or "Apply .... same style"; bit strangeImage may be NSFW.
Clik here to view.
Lilybiri
