My mil and mom both live about 10 minutes away, and they REALLY want to be a part of the whole birth and newborn thing, except..
Neither is comfortable or happy with homebirth, family bed, breastfeeding on demand, or pretty much anything with the AP stamp of approval.
I have to talk to someone (usually DH) after every conversation with them just to calm down.
My doula tells me to smile at them, say "Thank you," and then keep my mouth shut. I've tried that, but they're like pit bulls. They just don't give up.
My advice to you: First off, tell yourself 20 times a day (at least), "I am the only mother of this baby."
Also, set severe limits. And don't be sorry. Recognize that no matter how much you piss off these people, they won't ignore your new kid just because you wouldn't let them attend the birth or see the kid when it was one minute old.
Also, don't feel like it's your job to educate anyone about homebirth. You're pregnant. You've got better things to do. You're also sensitive enough to tell the difference between a open, honest question and a fear-based "question" that's really a value judgement. I had to hang up on a family friend who was practically my second mommy growing up, because she was so upset about the homebirth, and we're still effectively not speaking.
Something I did with my mom that worked for me:
She was angry, crying, screaming when I told her she couldn't come to the homebirth. Now, the reason why she's not invited is because she's been anti-homebirth from the start, and even though she says she "supports" me, she still can't get comfortable with the whole thing.
Her latest question: "How do you maintain a sterile field in a house with all those cats?"
So instead of reminding her about all the grief she's been giving me these last few months, I told her:
"Your relationship with this child is incredibly important to me. I want you to bond with this kid as early and often as possible. This kid will be blessed to have you in his/her life. I will make sure that you see the kid as early as possible, most likely when the kid is 3-4 days old. I promise that you will be the first person to visit the kid, before anyone else."
Amazingly this calmed her down. She just wanted to feel important, valued. The big side effect of her being anti-homebirth is that she hasn't been able to contribute anything worthwhile to this whole process, and in general, people close to you want to do that. So now I've given her something to look forward to, and she's calming down a bit.
As for MIL, I gave her the same speech. I told her she would meet the kid when he/she is 5-6 days old. She was incredibly unhappy about it, but that's mostly because she has travel plans which could get in the way, depending on when the kid arrives. Also, although she doesn't want to attend the birth, she did assume she'd get to meet the kid when he/she is less than a day old. Like your MIL, she pretty much said, "well it's your baby, whatever."
So I guess my advice is this: Find out what your mom and MIL want, and within reason, try to give it to them. Remember that they think they are coming from a positive place, they think they are helping you. Try to honor that by figuring out a way to help them. You may not get to win the homebirth argument, but heck, you're having one anyway, you already won. Better to make peace than wage a silly war..
Let me know if this helps. I've been where you are, and I know it's not easy.