2. Generally one, you can rent more if you so choose.
3. Never have had to wait, but Bud's has a large range, and I generally don't go on Saturdays.
4. Depends on the range. Bud's charges extra for every person on the lane, with a max of 3. Other ranges I've been to just put a maximum of 2 or 3 people per lane, and make you rent more lanes if you have more than that.
As far as general range advice, make sure you listen to the range officer at all times, and if it's your first trip, just tell the guy at the desk when you buy your range time. He'll either walk you through everything you need, or point you to someone who can. Also, keep your gun unloaded if you aren't at the line firing it, and whatever you do, make sure you don't accidentally hit the very serious looking gentleman with the precision target shooting .22 with your brass.
Hope you have fun! It can be a bit nerve-racking at the range the first time, but you'll be over it quicker than you think.