For each rainbow jello layer, heat the water in a pot over low heat. Add the remaining ingredients and stir the mixture until the gummy bears have dissolved. Pour each rainbow layer into a separate 6 x 9-inch greased baking tray, let cool, and then refrigerate for 2 hours until the jello has set.
For the cracker crust, combine the cracker crumbs, melted butter, and sugar and evenly spread the mixture over the bottom of a 6 x 9-inch baking tray lined with parchment paper. Refrigerate the cracker crust for 1 hour.
For the cheesecake cream, combine the cream cheese, powdered sugar, vanilla extract, and lemon juice. In a separate bowl, combine the unflavored gelatin powder and water and once the gelatin powder has dissolved, heat the mixture. Stir the warm gelatin mixture into the cream cheese mixture, gently fold in the whipped cream, and spoon the cheesecake cream into a piping bag. Remove the parchment paper from the baking tray containing the cracker crust and spread an even layer of the cheesecake cream over the crust. Then pipe 3 thick rows of cheesecake cream on top of the smooth layer.
Place the first rainbow jello layer on top of the 3 rows of cheesecake cream and carefully press it down between the grooves. Fill the grooves with cheesecake cream, place the second rainbow jello layer on top, and carefully press it down between the grooves. Repeat this process until you have used up all of the rainbow jello layers, with a rainbow jello layer being the top layer. Refrigerate the wavy rainbow jello cheesecake for 4 hours before serving.