First- I think it best that you don't discuss with your mom anymore. It always concerns me when there are people in the medical field who clearly haven't looked at any scientific research before they form an opinion of something (and then state their opinion as fact).
Also, a baby's heart rate speeds up a bit with contractions during a healthy labor and delivery. So, if they are going to use that as an excuse, that's not good. I remember the nurses commenting on DD's heart rate accelerations during contractions and saying that was a good sign that she was moving down.
Your own OB (who currently doesn't even DO VBACs) has stated that you are a good candidate and I'd assume he is more versed on the subject than your mother.
I had to switch hospitals and providers for my VBAC. I used a CNM and she was awesome. She had a back-up OB in the hospital if I needed a c/s but I knew she was not going to call one unless it was NEEDED. And that is the kind of providor I wanted. It sounds like you have really done your homework. RCSs are NOT safer. In many cases they are more dangerous than a VBAC. Both have risks and it is up to you to decide which way to go.
Good luck! And I know it is annoying when your mom is on you about things (my mom was also- she thinks midwives aren't as educated as OBs, but I think she is thinking midwives on the prairie or something). But you need to make your decision for yourself.