Grease cups of silicone mold with nonstick cooking spray. Set aside.
Use a jar or rolling pin to crush animal crackers placed into a re-sealable bag. Mix crushed crackers, butter and sugar together. Use a 1 tablespoon portion scoop to scoop into each of the 8 cavities in the prepared mold. Press down with your fingers to pack the cracker into the mold. Set aside.
In a mixing bowl, beat cream cheese. Add sugar, eggs, and vanilla and beat well. Use a 3 tablespoon portion scoop to scoop cheesecake mixture into each cavity.
Place 1 cup of water into the instant pot. Place the trivet onto a table and place the mold on the trivet. Use the handles to lift the mold into the instant pot. Place the lid on the Instant Pot and seal shut. Close the pressure release valve. Set the Instant Pot to manual, high pressure for 35 minutes. When the cooking cycle is complete, naturally release pressure for 20 minutes. Open the pot and remove the cheesecakes by carefully lifting the trivet out of the pot by its handles. Let set to cool before refrigerating.
When cheesecakes are cool from the fridge and you are ready to top, leave cheesecakes in the fridge and prepare the ganache.
In a small bowl, add heavy whipping cream. Microwave on high for 30 seconds. When the cooking cycle is complete, add candy melts. Stir well, at least 1-2 minutes. If desired, pop back into the microwave for 5 seconds and stir well until all candy is melted. Refrigerate for 15-20 minutes, stirring every 5 minutes. You want the color to change from a transparent pink to an opaque pink. You want it to be runny, but not too runny that it all runs off the top of the cheesecake. I refrigerated mine for 20 minutes.
Pop cheesecakes out of the mold onto a surface protected with wax paper. Spoon a dollop of ganache onto the top of the cheesecake, allowing it to run down the sides. Place a frosted animal cracker onto the cakes and add rainbow sprinkles. Repeat until all cheesecakes are covered.
Refrigerate until ready to serve.