Yes! Mavis Camera can accept an external multi-channel audio device as a source into the audio mixer. When using the advanced audio panel, the gain and pan on each channel can be modified.
Mavis Camera can only use one audio device at a time so all channels must come from the same input. It is also not possible to mix internally and externally generated audio sources.
For more information regarding Mavis Camera audio, check out this dedicated support article: Advanced Audio