Heat grill to medium. Whisk together 3 tablespoons honey and the orange juice in a small bowl. Brush the honey-orange mixture generously over the figs and then skewer figs. Grill, cut side down, until just starting to caramelize, about 30 seconds to 1 minute. Transfer to a serving plate and drizzle remaining tablespoon honey over top. Dollop with mascarpone and sprinkle with chopped pistachios. Serve.