All eight incidents are forms of plagiarism or academic dishonesty.
Some of these examples imply a more deliberate attempt to deceive than others, but in all cases the incident described constitutes an act of plagiarism. The best practice is simply to avoid the possibility that your reader might be left to wonder if the material you submit is your own. Always cite your sources. If questions arise concerning what facts constitute "common knowledge" or what forms of citation are acceptable for a particular assignment ask your professor.