In a small bowl, combine the sour cream, 3 tablespoons sugar, 1 teaspoon lemon juice and the lemon peel. Mix well and refrigerate.
In a medium bowl, toss the halved cherries and mixed berries with the remaining 1 tablespoon sugar and 1 to 2 teaspoons lemon juice. Refrigerate.
Break the chocolate into small pieces and place in a microwaveable bowl. Microwave on high, 20 to 30 seconds at a time, until the chocolate just starts to melt. Stir until smooth. Using a pastry brush, paint the inside of the cones with the melted chocolate. Place on a parchment-lined baking sheet and refrigerate until the chocolate hardens, about 15 minutes.
To serve, stand the sugar cones in narrow glasses. Place a dollop of the sour cream mixture in each cone, then fill with the mixed berries. Top with another dollop of sour cream and garnish with a whole cherry.