If we had the ability to create the tokens (as I suggested) they would be available to use wherever one would normally use them as well — so that would (naturally, hopefully!) be supported.
You certainly know your needs better than I could surmise, so if you need additional page layouts (or overrides) have at it. Though it sounds, to me, like you would need individual templates for each instance of a new token that you create and use, or overriding a template each time. I would personally avoid overrides if possible. 
Hello - I’m replying in this thread and hope it’s still active! I have similar (if not the same) issues as above. Lots of dialogue in a musical theatre score that needs to fit in specific measures and locations in the PV and full score but not in individual parts. I have generally just made the PV look right using shift x to type in and manipulate location - but obviously makes the full score a mess. I’ve recently been told (by AI) to change my workflow and to use system text and then in layout options select the players to not include and in the text option untick the box. Only I do not find a text category in layout options…am I close but just missing something? Does this sound like an approach that would work? Thank you all again.
While we’re wishing I’d like the ability to place a token in-line almost everywhere.
Bonus: conditional tokens.
I hadn’t scrolled back to the beginning to read other posts very similar to mine. It sounds like there is no good answer to dialogue cues really. Which kind of sucks for the musical theatre/opera world. I guess for now my option is for the full score to look very, very messy and use it just as a reference - and to make sure the PV looks right with all the dialogue cues. Thanks!
Perhaps what the plagiarismbot is aiming at is the option (added in Dorico 6.0) to exercise granular control over which system-attached items appear on which staves in a score. You can find it in Layout Options > Staves and Systems > System-attached Items. Set the toggle to Specific Players and you will find an array of checkboxes, with a column for System Text. However, I don’t know if that’s the best option, as it controls all System Text indiscriminately.
What I have done in the past is to paste every bit of Shift-X text to two places: the piano reduction (only appearing in the PV score) and one orchestral part, perhaps Violin I (only appearing in the full score). Then you have two independent instances of each bit of text which you can format and place independently of each other. And you can then locally hide all of the cues in the Violin I part, so they don’t affect that layout.
Admittedly, engraving such scores is still a lot of work but with this method, the mess gets significantly reduced.