Lock all settings to manual and you should be good to go.
Depending on type of stage lightings, I would lock WB to either daylight to tungsten.
If a lot of unfiltered Par cans, I'd use tungsten WB. If I see lots of Strobos and other moving lights, I'd prefer to set to daylight WB.
I'd lock all all 3 cams on same settings in the event of multicam live coverage.
Sometimes exposure have to be compromised when stage lights go full blast, but that's when the difference of good and lousy video cams sets in. Good cams have very good dynamic tolerence so over exposures are still pretty forgivable.
Here's a sample of my concert coverage for a band.
http://www.dxnmedia.net/MulticamDemo.mov