Having never read any of them I'd personally probably choose Black Elk Speaks, for three reasons. First, jews, blacks and gays are socially protected groups and I'm personally kind of tired of hearing about them. It's not unlikely that your professor is tired of hearing about them too. That leaves options 2 and 5, but 5 sounds terribly morbid to me. Leaving 2. Which you point out that you're not even entirely sure what it's about. And if others are also not sure, they're unlikely to choose it over the more familiar, socially obvious choices. Being the student who chose the topic that 90% of the other students didn't choose has its advantages when it comes time to papers being graded.
Second, I've read some of Carlos Casteneda's works, and if they're at all representative of drug-induced, american shamanistic/magical religious writing...#2 might make for an entertaining read. As in, entertaining enough to be worth reading even if you weren't taking the class.
Third, presumably you're taking the class for a grade and a piece of paper, but it wouldn't be so terrible to come away actually having been exposed to something new, right? From your description, I'm guessing that of the five groups, jews, blacks, gays, nuns, and Lakota medicine men...that last one is probably the group you know the least about.
So, Black Elk Speaks.
If you wanted a second option, I might suggest Malcolm X because he actually does have an interesting story. An awful lot of activists generally seem to simply be zealots with an agenda. Malcolm X was a zealot with an agenda who then actually grew as a person and changed some of his worldviews. That makes him more interesting in my opinion.