Welcome to alpine ski racing! It's a fun ride, and will teach you a lot about technique, line, instinct and conditioning.
Why do you guys hit every gate? It seems like it would slow you down, does it? Is it required? Or is it that your trying to hug your turn like the inside lane of an auto race and your inadvertently hitting it?
Hitting gates is (or, more correctly, should be) a product of good line: if you're cutting a tight line, the gate will be in the way and will need to be brushed aside. The tactic (in GS, which is the easiest point-of-entry into racing - NASTAR is a kind of GS) is to brush it aside, not to plow into the gate. Look at pictures of the best racers and you'll see that they try to allow the gate to slide off their upper back or up the arm, not plow into a square-angle hit on the collarbone. It is
possible to get tangled up and slow down if you plow into a gate or "thread it" with your arm.
That said, you shouldn't be reaching for the gate just to hit it. As I said, hitting gates should be the by-product of a good line. A lot of new racers will think they're doing something wrong if they don't hit the gates, so they'll reach for the gate, letting good technique, turns and line fall by the wayside. Concentrate on your turns and line, and the rest will fall into place.
If you want to get a good jumpstart, look into a racing or learn-to-race clinic. Many resorts offer them, either via the ski school or the resort's alpine race team. It's worth an inquiry. And some of the more experienced racers are happy to help if you ask - lots of former and current USSA and NCAA/USCSA racers are out there, racing in adult leagues, and would be happy to provide pointers.
Is there any racer etiquette, do's and never do's, stuff the average person wouldn't know?
It all depends on how serious the league is. If it's USSA Masters, it can be very serious, and it's good to listen for a while. If it's a beer league, then it's all fun and games until somebody loses an eye.
That said, don't tough others' skis and such unless you ask permission. Don't ski over others' skis. If somebody is visualizing the course, don't interrupt. Interpret body language in racing circles as you would normal social circles - that's the best bet.
Oh, and clear out of the finish area quickly - it can get crowded, and you're sometimes a sitting duck if you linger.
Above all: have a sense of humor, both toward your fellow racers and yourself. This will be a learning experience.
I'm a beer drink'n, smoke'em if ya got'em, turn up the jukebox kinda dude, will that fly with this crowd or is it more of a PGA fan type?
There's a reason that beer leagues exist in ski racing: a great majority of adult racers participate in beer leagues, have a lot of fun and enjoy the camaraderie of the sport.