I hid empty staves by using “Hide Empty Staves” under “Layout options”.
However, I think the bars which have staff attached text should be regarded as not empty.
Typically Shift+X text does force staves to show. Are you sure that those instruments are assigned to that layout? If so, we’ll need to see the project.
The crucial thing you couldn’t display in your screenshot is that all of those vocal staves are held by one player. You have a layout that allows instrument changes, which means that unless there are notes attached to multiple staves (held by that player), Dorico will only show one stave for that player.