Local bar that books a band that's playing its very first gig? The above is fairly likely. I recommend checking on that. If that's all they have, bring your own PA gear (and someone to run it, if possible). [Edit: I was thinking Sports Bar type gig. If it's an actual music venue with multi-band bills, then you're probably ok here.]Sometimes "house sound" is just a PA for you to plug into.
This exactly. Good luck.get there early
use the same rig you rehearsed with, nothing new day of show
if you have to setup and tear down quickly you should practice this a few times so that you have a good routine
lay everything you need to bring out on your floor before you leave, make a list if you need to and check things off as you pack them
bring backups for almost everything
have fun and stay calm even if something goes wrong, the crowd will most likely only know if you panic and freak out.
sound check is fine but don't noodle or make random noises when you aren't supposed to be
move around and get into the music, no one likes a motionless tree on stage
everyone in the band should keep an eye on everyone's gear