If the Soundcraft stage box is Dante capable then you should be able receive an audio stream from the addressable channels. You will not be able to control any aspects of the stage box from the Yamaha mixer such as gain or phantom power. You would be able to see and patch both devices from Dante Controller and if the Soundcraft had computer software to control the stage box as Yamaha has for RIO boxes then you could control the stage box functions from the computer.