You know, OP, I'm going to swallow my irritation and try to be kind here. I suspect that the reason you are trying to hurt your mother here (and you are clearly trying to hurt her) is because she has hurt you. You feel powerless and perhaps this is the only way you can think of to communicate to her just how hurt you are.
Despite some people's insistence that she must be pretty much sociopathic, I highly doubt it's that simple. From what little I can gather, she was married to a man who had no relationship with half her family, including their own child. Your family sounds all sorts of fucked up and whatnot. Whatever happened or didn't happen, I cannot see your mother as being a happy woman.
It's understandable to want to hurt someone who's hurt you, but ultimately it is, as the saying goes, like drinking poison and expecting the other person to die and telling them ten years before that you won't be at their funeral. You will not find peace by trying to hurt her, and you aren't setting a good example to your daughter. If there's really nothing to gain by having your mother in your life, perhaps NC is the way to go. No vitriol, no poison, simply removing the thorn. If you don't want to attend her funeral when it happens, then don't, but don't try to add pain and complication to it by telling everyone before it's even on the agenda. I mean, Christ, for all we know you might unexpectedly go first and then you'll look a right tit.
(That was supposed to be a joke, before anyone jumps on me.)
It's quite obvious your announcement to all and sundry hasn't made you happy anyway, or you wouldn't be posting about it here.