Hello,
You can find some more info here: Question Question Slides in Captivate - Captivate blog and Question Question Slides - Part 2 - Captivate blog Nothing has really changed concerning question slides in 8.
The grey shaded review box is not really used any more (since 6?), just when a quiz slide has been skipped and on the score slide (for the Success/Failure message). You cannot enter anything.
As for the Next button (necessary in Review mode) that can be a Skip button during the Quiz I mostly hide it during the Quiz by dragging that button under the Clear button. Default stack order allows that. This is one of the workflows described in the blog posts.
Lilybiri