That's Absolutely vile of your sister to do such a thing & try to cause this strife between you two. As others have stated Definitely call her out on her foul behavior so she can realize how shameful of a person she really is.

Personally I would explain to her that what she is doing is rude, selfish, and is going farther than just "stealing a name". I'd explain the emotional side of it and the fact that I would no longer support her in her pregnancy and that she and her family will no longer be welcomed at my house. I would explain that I will not be forced to go through emotional torture to "keep the peace". I would also explain this to other family members. It wouldn't be a "fight" or negotiable. If you want to be a **** nugget then that's fine but you won't hear from me anymore and you certainly won't see me anymore. Usually if you explain this to people calmly and let them know this is the FINAL option they will get then they may have a change of heart. Also OP, I want you to know that there was nothing you did wrong to cause the miscarriage. People don't talk about it enough and women are shamed for it, but something like 1/3rd of all pregnancies end in miscarriage. So I want you to grieve for your little girl but I don't want you to beat up yourself. idk if you do this, know this, but I just want that out there.

Don't name your kid before it's born, and don't tell people what you plan to name it before it's born.

The only way I can see this being halfway reasonable is if "Hana Grace" is a family name. My sister and I have both talked about naming our hypothetical sons after our grandfather, although we're planning for the names to be slightly different to avoid confusion. Still, family name or no, it sounds like the sister is being incredibly callous about OP's loss. And if it's not a family name, she's either an utter asshole or not remotely thinking about OP's feelings.

I'm so sorry about your miscarriage, and that's a horrible thing for your sister to do. But at least you'll never forget your daughter as you watch your niece grow up. Not that you would, of course!!!

That's horrible

Your sister is disrespectful, unless you gave your consent. Is this meant to honor the deceased? Or take what is left of your child?

I'm sorry that's awful. You need to explain to her how insensitive and hurtful that is. Maybe get your mom involved if you three are close.

Get a head stone? Not really to be petty but show her that what she's considering is extremely hurtful. I know you probly don't want anything around to remind you tho.

Hi guys, OP here, thanks for all your words of support and condolences, I very much appreciate it. I've talked with my sister and she finally understands how hurtful ishe was being and has decided on naming her daughter Ashley LeighAnne instead. Wounds are still sore, but we will be alright. My sister has never been very bright at things like this. She's always been unintentionally insensitive and I hope having a baby changes that for her. Anyways, thanks you guys!