Thanks for all your help!
Show went well, and they sounded great, despite the challenging environment and the fact that this was a live test of some of the gear for the first time.
The key piece of advice that served me really well was keeping volume on stage as low as possible.
That way the primary source for the crowd was up front, aimed away from the ceiling and and overcame the reflected junk.
You could actually hear all the elements in the mix, whereas other shows I've seen at this place were all guitar and drums with no vocals, keys etc..
If anything, I kept the guitars a little too low, but I got no complaints from the crowd.
Main thing was the singer sounded great, strong and clear in the mix, and she's somewhat on the quiet side normally so that was a primary concern.
And no feedback issues.
The two things that surprised me that I need to dig into are:
The kick drum didn't have a lot of presence in the subwoofer.
Maybe my mic position was bad (AKGD112 just in front of port), or it's a quirk of the Yamaha kit my daughter uses.
But it didn't seem to move a lot of air in the sub. The line in from the bass-amp sounded great on it though, so I know the sub was working.
Perhaps her kick just doesn't generate frequencies quite low enough for this sub?
And there was a ton of bleed from the snare into the kick mic. Frankly there was a lot of bleed between the drum mics in general.
I was using the drum presets from Master Fader, and had hopes the gates would help more than they did.
Live and learn.
Thanks again for all your help!