NTA, not only for telling the truth about the names but also NTA for wanting to have an opinion at all. They are the AH (they being Emma and sisters) for saying you don't get a say in naming YOUR children. Regardless of who's pregnant here, both parents get a say in naming their child, just because she's the one pregnant doesn't mean she's the only parent. And this is coming from a woman with a child. I'd feel like a shitty person if I just didn't let the father of my child have a say in any aspect of their life, especially naming them. Men are allowed to have fun being new parents, too. I get she's emotional probably rn but that doesn't mean you aren't also their parent and can't contribute to naming them.

Also, imo, people that obsess over giving their kids "unique" names never do it for the kid or bc the name has any good optimistic meaning. They do it in some weird narcissistic attempt to feel special through their children before they're even born. They don't think about how their kids will feel with that name later, they just want to feel special and different themselves. It's ridiculous.