So far my in-laws have been great, of course we don't plan on having anymore children, so I wont be faced with any of the issues you have presented.
First, keeping your last name is your decision, and yours alone. Yea, I can see where the older family members could see that as a bit disrespectful and so on, but you have to realize that it's been a part of almost a world wide tradition for so long, some times it's harder for people to accept change than others.
In my opinion your birth plan sounds completely acceptable and well within reason. You are the person giving birth, you and your husband should be able to call all of the shots, well as many as can be controlled. I was always told that if there was something bothering you, or if there was someone who was being bothersome, tell the nurse. Make the nurses be the bad guy. I did that, I asked my nurses to ask people to leave and so on. It helped on me being sought as being selfish and what not. I think that now, yes the in laws might have a problem with the guidelines that you have put down, but once the baby comes, they'll have to come to terms with the rules, or they wont be able to see the baby. I actually got so sick that my nurses and my mom had put a sign out on my door that refused visitors, my family and ex in laws were forced to abide by them. My motto is "Like it or Lump it".
You're doing great, hang in there!