I believe that your friend has inserted herself, or that you have allowed her to become inserted, in your marriage and in your childbirth experiences in a way that is very inappropriate.
It's perfectly fine, and normal, to get friends' opinions about names. It's perfectly fine, and normal, to wait until the baby is born to look at the baby and say "you definitely look like a [Michael or Josiah or Amelia or Elizabeth Ann] so even though we had other names picked out, these just sound right" or "he looks just like Uncle Samuel so that's what we'll call him" or even to give it a few hours.
However, what your friend is doing is not fine, and it's not normal. To be angry about this, to insist that a name be chosen and revealed, to want to monogram things in advance, to plan naming games, to be THAT involved that a fight develops, well, that's unhealthy and wrong. Sometimes, a friend assumes an inappropriate role in a relationship. Sometimes it's because of that person's insistence, or lack of a personal life, or just the extreme desire to micromanage other people's lives. Sometimes it starts innocently, and it just snowballs, and before you know it, that person is just too close. It's time to close up the boundaries. This is not something that a female friend should have control over. Input, sure. Anger and control, no. It's as though you had a burglary, and you ended up feeding the burglar and inviting him to stay in the guest room.
The only way to handle this is to be honest. It ISN'T her choice and it ISN'T her business. You will need to tell her to respect your choice. Tell her you value her friendship but she will not have executive decision making privileges about what - and when - you name your son.
As for your dad's name, I respect your situation. Is there any way you could find a variation of your dad's name? If his name is James, for example, could you call your son Jameson, or Jamie, or Jeremiah, or Jacob? You can look up a name online and google variations of the name.