Process raspberries, strawberries, honey, lemon juice, and salt in a food processor until smooth. Stir together yogurt and buttermilk. Fold yogurt mixture into berry mixture. Pour into 10 (2-oz.) pop molds. Top with lids; insert craft sticks, leaving 1 1/2 to 2 inches sticking out of pop. Freeze 4 hours or until sticks are solidly anchored and pops are completely frozen.