Listen to Tom...
As for safety gear, I agree 100% with the PFDs at all times. I would also have a throwable PFD, with a line tied to the boat, and easy to access.
With kids, you really only have two enemies: boredom and fear. Keep it fun and safe, the rest will take care of itself.
Mike
I agree 100%. When I was a newbie in relatively light air I got an unexpected gybe that cold **** me by the boom. I had no PFD and fell back on the boat. I was close to shore and the boat just sailed itself down wind in to beach. If I had fell off I would have been a goner.
Doug