Pumpkin Praline Trifle

Ingredients

• nonstick vegetable oil spray
• 1 cup (packed) golden brown sugar
• 1/2 cup sugar
• 1/3 cup half and half
• 1 1/2 tablespoons unsalted butter
• 1 teaspoon vanilla extract
• 1/4 teaspoon salt
• 1 2/3 cups pecan halves (about 6 ounces)
• 2 cups chilled heavy whipping cream
• 1 8-ounce container chilled mascarpone cheese
• 1/4 cup sugar
• 1 teaspoon vanilla extract
• 1 15-ounce can pure pumpkin
• 1/2 cup (packed) golden brown sugar
• 1/4 cup heavy whipping cream
• 1 teaspoon ground cinnamon
• 1/4 teaspoon freshly grated nutmeg
• 1/4 teaspoon ground allspice
• 1/4 teaspoon salt
• 1 1/2 3-ounce packages soft ladyfingers
• 4 1/2 tablespoons dark rum, divided