In addition to everything else mentioned here, make sure the high pass filters are turned on in the amp, put it in the 50hz position. That will help a tiny bit to keep the amp out of clipping and help keep the woofers from being beat to death. Don't expect or try to make those speakers to shake the room with every kick drum hit.
Since everyone is on in ears ditch the bass amp and go direct with the bass, if you can put the guitar amps in a back room and mic them up or go direct with them as well if they have decent guitar processor pedals also keep the monitors as low as can be.
Doing that will keep you from pushing the system just to overcome the stage volume.
