Re: Clarity not Volume
Make sure if there are electric guitars that they're not scooping their mids. Some folks like that smiley face curve on their amp, but then it can't be heard in the mix.
On amps, I play a fender, and the other plays a Vox, which helps. We also make sure we're usually playing very different parts so that you don't have the "molly hatchet" effect of everyone trying to do the same thing. So even when the keyboard player picks up a guitar, it's 3 different parts that work together vs. all trying to strum the same chords.
We had to convince our keyboard player to play an octave higher to get out of the guitars - now his parts are loud and clear.
I'd get the band orchestration settled first without PA, and then add to reinforce to taste.
