MAKE THE CRUMBLE BASE: Combine crushed cookies, melted butter, and brown sugar in a mixing bowl, stirring until the mixture resembles damp sand. Spoon 1–2 tablespoons into the bottom of each clear serving cup and press gently to create a firm base. Set aside.
PREPARE THE THICK RED LAYER: In a medium bowl, whisk together the red gelatin powder and unflavored gelatin with ½ cup boiling water until fully dissolved. Stir in ½ cup cold water and the cherry pie filling or mashed strawberries. Blend with an immersion blender or mash until mostly smooth, keeping small fruit bits if desired. Allow to cool to room temperature, then spoon over the crumble base in each cup. Refrigerate for 30 minutes or until the layer is firm.
MAKE THE MOUSSE: In a mixing bowl, beat the cream cheese until smooth. In a separate bowl, whip the heavy cream with powdered sugar and vanilla extract until stiff peaks form. Gently fold the whipped cream into the cream cheese mixture until smooth and evenly combined. Spoon or pipe the mousse over the chilled red gelatin layer.
PREPARE AND ADD THE BLUE GELATIN: Prepare blue gelatin by dissolving it in 1 cup boiling water, then stirring in 1 cup cold water. Let the gelatin cool to room temperature before spooning it gently over the mousse layer in each cup. Chill for 30 to 40 minutes until completely set.
TOP AND DECORATE: Just before serving, pipe a swirl of whipped cream onto each mousse cup and decorate with red, white, and blue star sprinkles.