first, congrats. you will have many new fishing friends.
tips:
get a backup (third) oar in case you break one
all that coast guard stuff
life jackets(the pull to inflate ones are great)
ask around about easier floats, start there
take someone who knows how to row and is familar with that float. youll learn more and youll get to fish instead of just row(guides are best but anyone with experience is good.)
The tip on keeping all plugs out the same distance is great but make sure you all use the same type,test line. otherwise the plugs act differently.
Lastly: eventually, you will hit a rock. If you know you aren't going to miss it, at least hit it with the bow. if you keep your cool and keep working the oars, you'll likely spin around and you can pull hard and off the rock if you hit square on the side by the oarlock, your upstream side will likely be pushed down and swamp you before you can say @$&**@%