Yes, you can replace the ducted Dometic air conditioners in your 2015 Landmark Newport with Furrion Chill Cube units. The Chill Cube series is compatible with ducted systems like yours, which feature small round supply and return vents. To complete the installation, you will need the Furrion ducted air distribution box that connects the rooftop unit to your existing ductwork, as well as the matching Furrion thermostat and controller since their wiring and communication differ from Dometic systems. Some wiring adaptations will be required due to these differences. The standard 14" x 14" roof opening used by your current Dometic units is compatible with the Furrion Chill Cube units, making the physical swap straightforward once the necessary components are installed.