Heat oven to 425°F. On large rimmed baking sheet, toss Brussels sprouts with 2 tablespoons oil and 1 teaspoon each salt and pepper. Arrange cut sides down and roast until golden brown and just tender, 20 to 25 minutes.
Meanwhile, in small skillet, melt butter and 1 tablespoon oil on medium. Add pepitas and cook, stirring occasionally, until pepitas are golden brown and begin to make a popping sound, 5 to 10 minutes. Transfer to paper towel-lined plate and toss with chile powder, cinnamon, coriander, and 1/2 teaspoon pepper.
Finely grate 2 teaspoon lemon zest into large bowl, then squeeze in 2 tablespoons juice and whisk in remaining 2 tablespoons oil. Add Brussels sprouts, figs, and pepitas, and toss to coat. Season with salt and pepper if desired.