Grease silicone mold. Crush animal crackers. Mix with butter and sugar. Scoop into mold. Beat cream cheese. Add sugar, eggs, and vanilla. Scoop cheesecake mixture into each cavity. Place 1 cup of water into IP. Place mold in IP on a trivet. Seal shut. Set the Instant Pot to manual, high pressure for 35 minutes. When complete, naturally release for 20 minutes. Open the pot and remove the cheesecakes. Refrigerate. Microwave heavy whipping cream on high for 30 seconds. Add candy melts. Stir 1-2 minutes. Refrigerate for 20 minutes, stir every 5 minutes. Pop cheesecakes onto wax paper. Spoon 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. Refrigerate until ready to serve.