Aww, my first trip to NYC was for my 16th Birthday and I spent every morning in line with my uncle at the WTC TKTS with a doughnut and coffee. HAHA. Oh, memories.
I agree with everything thats been said. TKTS in times square at the height of summer can take 2 hours in line, and usually you're standing in pouring rain, or extreme heat. Best to get them through a discount code (I imagine most of the shows you mentioned will have them by then, even during the summer), or at the other locations so that you have more time to see the city.
But, if you are dead set on times square TKTS
1) Get there early if you have your heart set on a particular show. The lines start usually an hour before they open (3pm for evening shows). If you don't really care that much, get there around 5 or 6 and the lines are usually much shorter and quicker, or even non existent.
2) The seats are a total crap shoot. Usually they are side orchestra, and there isn't necessarily a correlation to the time you get there and the quality of the seats you get. It all depends on what they have at the booth when you get to the window.
3) I can only speculate what the discounts will look like. My advice is to track the discounts on the board for the shows you are interested in. That will give you a good idea. There is a website out there with this information, but I don't have the link handy.
Good luck, and bring good shoes.
"If this is going to be a Christian nation that doesn't help the poor, either we have to pretend that Jesus was just as selfish as we are, or we've got to acknowledge that He commanded us to love the poor and serve the needy without condition and then admit that we just don't want to do it." -Stephen Colbert
