Line 2 baking sheets with parchment paper. Toss the cereal, pretzels and cookies in a large bowl. Combine the white chocolate chips, butter, lemon curd and lemon zest and juice in a medium bowl. Microwave at 50 percent power in 15-second intervals, stirring, until melted, 1 to 1 1/2 minutes; whisk until smooth.
Pour the white chocolate mixture over the snack mix; toss to coat. Sprinkle with 1 cup confectioners' sugar and the powdered gelatin and toss again. Spread on the prepared baking sheets and let dry, 30 minutes. Toss with the remaining 1/2 cup confectioners' sugar. Divide among cellophane bags.