Thank you for the hard work and thought you have put into this. Here are some thoughts on the nominees:
Brave New World and
1984 are, perhaps, a bit too familiar and have been discussed over and over. (They are both worthy of such attention, of course.)
The Jungle is an interesting choice. Could lead to some discussion of the ways in which food and drug quality have been regulated, although that is not at all the main point of the booK.
Anthem might be the most passionately discussed, as very few people are neutral on Ayn Rand. This particular book has the virtue of being short (as opposed to Rand's usual gigantic volumes) but it was obviously strongly influenced by the 1920's Russian novel
We by Yevgeny Zamyatin (which seems to have influenced the first two books on this list as well.) (I can't find the text of
We in public domain, so it may still be in copyright. Anybody know? If not, I'd nominate it. It's short, funny, and thoughtful.)
Up From Slavery is a fine book. I'm not sure how much discussion there would be beyond "slavery is bad" but there might be some. Was Washington's approach to the problem of civil rights (as opposed to, say, DuBois) the correct one?
The Wealth of Nations, although undeniably extremely important, is pretty dreary reading. (Hint: It's about economics.) I suppose one should nominate
Capital by Marx to show the other side; they're both pretty heavy reading.
Which leaves me with
Civil Disobedience, which I think is a fine choice. It's short enough to grasp as a whole; it's not as familiar as most of the other works on this list; and it's wide open for discussion. It gets my vote.