If they are wedges or mono in-ears they should be mono. If your band is using stereo in-ears and is actually using the stereo component of it (panning different sources) then they should remain in stereo.
If you can switch to mono, you can double your number of aux mixes or allocate those for other types of mixes like subgroups or matrix mixes. Changing from mono to stereo is done by pressing the “Setup” button, then going to the config tap across the top of the screen. After changing the config, you will need to go to the I/O screen and patch your new mono aux mixes, and then assign them to the surface controls as well.