According to the setup shown in the screenshot, I believe that there should be 6 staves visible in the full score: all players are checked, all flows are checked (off-screen), and in layout options Hide empty staves is set to Never.
You have 2 empty players (Cue and Edited Cello), so nothing will ever show for them.
Your Harpsichords are showing as single stave. Just change one to Harpsichord and it will add the missing stave. You can then copy/paste Harpsichord 2 into Harpsichord 1 and delete the later.