I have streamed audio and video from various tablets and phones using different interfaces, depending on what I needed.
If just sending audio, yes, sure, run from the headphone out of the Mackie to an audio interface (I use an iRig 2 channel).
A buddy of mine streams via a phone in the field and uses his mixer's audio output to run to his camera's audio input, then that camera feeds audio and video via hdmi to an interface...