Aren't Hegel and Nietzsche too late to be considered Enlightenment philosophers? I'm intentionally not looking it up since I wanna see if I pass the test too... I'll add Hume and Spinoza as replacements, but please don't ask me to elaborate on what any of these people actually contributed to our societal body of knowledge :)

Speaking of Hume, I rather enjoyed this article: http://www.theatlantic.com/magazine/archive/2015/10/how-davi...

I would have had a similar list (decreasing order of confidence as well). Kant, Voltaire, Descartes, Heidegger, Kierkegaard.

I don't think this is something people should necessarily know. Ask them to name some 5 philosopers and be happy if they can do that, but specifying a period? A tad too hard I guess :-)