1. Read it, teach it beginning to end.
2. Read some, teach about them.
3. Yes, teach it.
4. Read it a long time ago in college. Thought it was one of the most boring things I'd ever read. I teach about it using portions and summary.
5. All 5 volumes? No. I've read and studied parts. Teach about it using portions and summaries.
6. Read some, teach some.
7. Yes, teach it.
8. Read some. Teach about Locke quite a bit in conjunction with his influence on Jefferson and the Declaration of Independence. Teach a little about Leviathan.
Maybe you should add Adam Smith as well.
I had to study and read the works of all of those guys to some extent. My specialization in college certifies me to teach - American History, World History, Economics, Political Science, Geography, Psychology, Sociology, and Anthropology. The only one that is really burned into my brain though is The U.S. Constitution. I've been teaching it first sentence to last, discussed and debated, for 26 years now.