Re: Night fly fishing
Don't know the area at all, but if you have boaters zipping around you might want to have a whistle on a lanyard too, along with some sort of waterproof top with a wading belt cinched tight to keep water out if you step in a hole. You can put a vest on over it. Since you're going with friends it would be a good idea to at least keep in voice contact with each other while your in the river.
In addition to buggers you may also want some big flies that push a lot of water-- black rabbit strip or muddler/sculpin type patterns in size 2 and 4, and depending on the line you're using, some heavily weighted ones to fish deep with a floater or unweighted to fish with a sink tip and short leader, which might be a bit easier to manage at night, and also very effective. Casting heavily weighted flies on long leaders at night can be a little hairy, so you may want to pinch the barbs down. If you're throwing big stuff like that a 7 or 8 weight wouldn't be out of place if you have something like that.
I'd add some shad patterns in the event there is a shad kill after a cold snap that can trigger binge feeding.
There are some very big fish down there so throwing some meaty stuff might really pay off.
Not to put the cabosh on it, but I'd also try to give some thought as to how and where you'd land a fish if/when you hook one, and at least have some sort of plan before hand. It can turn into a real circus in the dark, but if you make a mental note of where you can beach a big fish, or where potential snags are to steer fish away, routes you can take to follow it downstream if you need to chase one (without breaking your neck) it might help make a difference if you get a good one on. Better to have a plan and not need it than... Up here in the NE I've seen guys lots of times fishing in SW for stripers casting from places where the chances of landing a hooked fish are exactly zero--- and that's in broad daylight. It can be worse in the dark.
Scouting in daylight also may give you a good idea of stretches of water you can cover by moving, casting three times or so and swinging flies taking 3 steps repeat, to cover a lot of water. It would be good to know where ledges are before hand so you don't step off one at night, or spend lots of time standing where you should be fishing while casting out to unproductive water (And BTW, I've done both more than once.)
And, if you're fishing around rocks, get in the habit of checking your hook points periodically. It's easy to roll a point, or even break off a point on a backcast. I've done that too. You can easily check with your fingers without a light.
It's surprising how much your other senses kick in when you're fishing at night. You should have a great time.