How do I get my MIL to call my son by the name we chose?

My fiance and I are expecting our first child together. It's a boy. We've decided we like the name Rory (it means red king and my daughter Ruby's name means red, so it's a theme, we didn't even know what the name meant until after we picked it, lol). Anyways, my fiances mother doesn't like the name. She also says she can't pronounce it (It rhymes with Corey, Tori). She wants us to name the baby after my fiance, so that he's a Jr. We don't like that idea, but whenever we refer to the baby as Rory, she smirks and say's "You mean Brandon Jr/Jr". That's all she ever calls our baby and keeps cornering my fiance alone and pressuring him o name the baby after him and keeps calling the baby Jr whenever I call him Rory. It's driving us insane! I feel like she's being rude and disrespectful to both of us. I don't want her calling him this when he's born, I want her calling him by his NAME. Also, she and her daughters keep pressuring us to give the baby my fiances and fiances fathers middle name, which is Wood. We don't like it and want to give the baby a different middle name bu they say it's a family name and keep trying to make us feel bad and guilt trip us into doing it. What can I say to them, that isn't nasty? I know it's our child, so we obviously don't have to listen, and won't, but what can I say to get them off our backs? Help please? Thanks!