You have lots of good advice already; I just want to expand a little on question #3. As already remarked, it's important to make the amount of time clear in your communications -- after everything is agreed, sending a short final summary message along the lines of "looking forward to seeing you on [date] [time] for [amount of time] at [place]" is a good idea. I hate being responsible for time-keeping, so I normally -- at the beginning of a session -- say something like "I'm going to rely on you to keep track of the time." *
With someone inexperienced or flaky, these precautions might not work, of course.
And with someone you have hired multiple times, these precautions are probably unnecessary. They are meant for guys you haven't been with before and for inexperienced clients who may be nervous about how this will all work.
Good luck and have fun.
*Here's the very smooth way one escort handled the time issue with me (we had really hit it off and I had no sense of how much time had passed): at a lull in our activity, he gave me a big kiss and asked if I wanted to extend for an additional hour (I think we were well past 75 minutes by then).