1. Very hard. It depends on the show, but Into the Woods has been very popular. Get there between 5 and 6 AM.
2. Yes, the weather is a concern, but it usually isn't too cold in NY in August. I would worry more about rain. They do cancel the performance if it's raining very hard or if there are thunderstorms but they try to run the show.
3. There are actual seats with a back but they're hard plastic. Not the most comfortable but they're fine. You are allowed to bring seat cushions, blankets, etc. to make it more comfortable but I've never had an issue with that.
4. 100%! I think the time in line can fly by especially if you bring a lot to do, can get some sleep on line, or can talk to people. I've never felt the wait wasn't worth it.
Scratch and claw for every day you're worth!
Make them drag you screaming from life, keep dreaming
You'll live forever here on earth.