First, I'm going to move this thread to the SW
Getting Started forum, you'll get more help in there.
1) I don't recommend using crushed coral (cc). Stick with dry aragonite sand, you'll be much happier in the long run. How much you need depends on how deep you want it to be to get the look you're after.
2) See #1
3) Generally 1-1.5 pounds per gallon is pretty good to go off of, but it depends how you want your tank to look when it's all setup.
4) Once you get the new tank established you'll be able to add additional fish
5) Never kept one, so not sure.