Thanks for the visuals.
A couple of thoughts:
1. You've shown the sub-group meters and set your channel input gains @ -15 as suggested. Cool that that makes the problem less critical. But there's one more thing I would like to know about the metering. If you use the FatChannel LED's in the "Output" mode, what levels are the individual channels hitting while the sub-group meters are as they are? Just a double-check....
2. If you're showing that much stuff into the vox mics with no voices on them I'd recommend that you use your "expanders" on them. It's somewhat like gating, but not a hard "on/off" situation which can be audible and distracting. Set your threshhold for the expanders as high as you need to lessen the amount of bleed from the unused mics and set your release adjustment @ around 1.0. This will help clean things up a bit. The expander/gate selections are by channel pairs (1/2, 3/4, etc) and are set in the System menu, page 4 of the Master section.
3. If you solo the vox mics and listen in the headphones, you'll be able to identify the worst offenders in the stage wash: drums, amps, etc. Then you can start to work on those issues by deploying some deflectors between the kit and the voice mics, turning the guitar amps to face across the stage rather than at the mics/audience (a much discussed topic around here) and just getting them to turn the amps down, use smaller amps or whatever it takes to let you dictate the mix in the house through the PA rather than limit your job to pushing vocals over the stage wash.
Enjoy. Looks like you're getting along well.