Hi Joseph,
To use only one cable between FoH and Monitor consoles I would suggest moving the Dante card (and recording) to the FoH position, then add an SLink card to the Monitor console.
This way you can use Tie Lines from Monitor to route the DX168’s on stage to FoH.
You can also return the FoH mix to Monitors and use Tie Lines to route to the main sound system.
If you need to keep Dante and recording at the Monitor position, you would need to run two cables and connect the DX168’s to the FoH console, then add an SLink card here to run back to Monitors.
Hope this helps!
Cheers,
Keith.