The trouble with replying is that whatever you say you're inviting another reply, further engagement, which is going to suck more of your energy and lead to another reply....more energy, more headspace wasted on this woman.
As others have said, you cannot win with someone like this. She is not a reasonable or decent person, she sees you as a threat to her power and she is not and never will be on your side.
The trick with such a person is to behave normally and politely, and simply ignore unpleasant behaviour. So send an invite to your naming ceremony, and if they come (which I bet they will, if only to be extremely pissed off about it) then that's fine.
But engaging with these ridiculous emails is beneath you. And if you simply withdraw and refuse to take the bait (rather than commit yourself in writing to something that could be used against you) then she will run out of steam. And soon enough, she will become smaller and smaller in your mind and you will be free of her mind games and bad behaviour.
Trust me on this, I have people like this in my life and the only way to beat them is to ignore them, they absolutely hate it! Remember, revenge is a dish served cold (and with an icily polite smile....!)