1. "Neither . . . nor" is correct. "Not . . . nor" is incorrect. In terms of the next sentences, I'm not sure whether "never . . . nor" is correct (it's usually "neither . . . nor") but in everyday conversation people rarely use "nor." It sounds a bit pretentious or literary, depending on the context.
2. Not 100% about the rule in this case, but "either . . . or" sounds better here, when you're starting with a negative.