I'd like to point out one thing about point 1:
In junior high, there was this boy in my class who often interrupted the teacher (in lessons where raising your hand to speak wasn't a must, like art) and got yelled at for it. However, the boy was autistic. People can usually tell when someone is finished with their talk from... I'm not sure from what, but from something, some facial expression or whatever. However, some of us autistic people have trouble with that. Keeping that in mind, it's not weird if we get interrupted by NTs a lot since they might see that "something" in us while in reality we haven't stopped talking.
But yeah, interrupting someone when you know they aren't done is rude.