Is there any way to attach a coda sign to an empty measure with hidden rests?

[Lillie_Harris]

Or you can turn off multi-bar rest consolidation in the layout (if I’m right in thinking you said you don’t need multi-bar rests?) to avoid the need to position items rhythmically based on rest appearance.

Rests hidden in score but not in part

The issue is that if the only thing in a bar is a chord symbol on the first beat, Dorico treats the bar as a multi-bar rest (albeit one that’s only a single bar long). The rest you see in the part isn’t the real rest you’ve removed in the score; it’s the visual padding shown in any multi-bar rest. You could turn off multi-bar rest consolidation for this part layout, from Layout Options. If you need multibar rests elsewhere in that part, report back and someone will think of a hacky workaround. …

That said, I’m not sure the coda should move or not appear based on the rhythmic position of the chord symbol. Can you share the project, or a version of it just containing this section?