"I don't like neither of you" -> In this sentence I think the meaning is that the person doesn't dislike any of the other people.
"I haven't done it neither" -> This is just a confusing double negative, meaning, I haven't done it not either, so I've done it, right? (I'll never ever say this, don't worry)
"She isn't cute nor pretty" -> And this is where I'm confused, I think the meaning of this sentence is that she is neither cute nor pretty. But I don't know if nor can be used with a negative statement before, because it might be changing the meaning of the sentence (??? -> I'm not sure if what I've said about changing the meaning of the sentence is correct)
"I don't like either tomatoes or beans" -> I like neither of them, right?
"I either don't like tomatoes or beans" -> If somehow I could choose what to like and what not to like, this sentece would mean that I had chose between one of them, right?
"I either don't like tomatoes or I don't like beans" -> The meaning is basically the as the previous one.
And that's it, keep in mind that all these senteces have just been made up, so they might seem a little out of logical context, like the tomatoes and beans ones. I'd like to know if I'm correct about the meaning of these sentences.