Mom is treating engagement like a hostage situation

If it isn't important to you then I would just ignore your mom. However, I can tell you it was important to me that my husband asked my dad. My sister's husband didn't ask my dad and I know my dad was hurt her husband didn't ask, but he hasn't held it against them.

Cut all ties with your mother now and anyone who supports her. Abuse/control is never acceptable. A narcissist will always gaslight you in believing they are correct and you are crazy. So don't allow it to continue. People like this never see anything wrong them so they don't feel any need to change.

That aside, many couples do not for parent blessings because they feel that if you are mature enough to get married, you belong to yourself and make your own decisions without other's blessings/input.

Since she has been unwilling to get to know him, that's her own fault. A last name is no reason why you shouldn't get to know someone.

Yikes I hate this for you! I will say, and this may be a southern thing, but my dad probably would have been crushed if my fiancé didn't ask for his BLESSING - not necessarily permission. It's a very old school, traditional thing, but it was very important to me that he ask my father before proposing to me. Granted, my fiancé and my parents are extremely close and there's never been any hostile talk on our relationship & it wouldn't have been a deal breaker if he hadn't of talked to my dad first.

If this isn't important to you, or a tradition you want to follow, you absolutely do not have to! I think your mother sounds very controlling and I agree with others that you may need to cut ties if this is just how she is. That's all depending on how much you value your relationship with your mother. I would definitely think on it