Put the pecans on a baking sheet and bake until toasted, 8 to 10 minutes. Remove from the oven, cool and then chop.
Crumble the cake into a large bowl.
Put the heavy cream and chocolate chips in a medium heatproof bowl and microwave in 30 second intervals, stirring after each time, until the chips have melted and the mixture is smooth.
Line a baking sheet with parchment paper. Sprinkle the rum over the cake crumbs. Then pour the melted white chocolate over the cake crumbs. Add the pecans and stir with a fork to combine and moisten the cake. Squeeze about 2 tablespoons of the cake crumbs in your hand and roll into a ball. (A small cookie scoop helps to portion the cake; just press it firmly into the scoop, remove and roll in your hands to form a ball.) If you have trouble with the cake sticking together, add cream and/or rum, about 1 tablespoon at a time, until it does. Repeat with the remaining cake crumbs. Place the balls on the prepared baking sheet and refrigerate for 2 hours or freeze for 30 minutes. Remove 5 minutes before using.
Put the green candy melts and 1 tablespoon of the coconut oil in a medium heatproof bowl. Microwave in 30 second intervals, stirring in between, until smooth. (Alternatively, you can melt it over a double boiler.) If the chocolate is still thick and not smooth, add more coconut oil 1 teaspoon at a time until smooth. Let the chocolate cool 1 minute before dipping.
Dip 2 inches of a lollipop stick into the green chocolate, rolling to coat and removing any excess. Insert the green end into the center of the cake ball, so about 1 inch of the green is exposed. Repeat with the remaining lollipop sticks.
Put the orange candy melts and 3 tablespoons of the coconut oil in a medium heatproof bowl. Microwave in 30 second intervals, stirring in between, until smooth. (Alternatively, you can melt it over a double boiler.) If the chocolate is still thick and not smooth, add more coconut oil 1 teaspoon at a time until smooth. Let the chocolate cool 1 minute before dipping.
Dip each cake pop into the orange chocolate, taking care not to get any on the green stem. Let the excess chocolate to drip off and then put back onto the parchment-lined baking sheet. Then dip the pops one more time in the orange chocolate. Refrigerate for 5 minutes.
Put the remaining green chocolate (about 1/4 cup) into a disposable pastry bag or zip-top bag. Pipe vines and leaves on top of the cake pop where the stem is.