Add butter and peanut butter to the stand mixer bowl and cream together. Add the fondant and salt and continue to mix on low. Pour in milk slowly and bring speed up to medium until well-blended and creamy. Refrigerate overnight in a sealed plastic bowl.
In a small pan, heat the corn syrup until it is very hot. Do not boil!
Put the coconut into the mixing bowl and pour the hot corn syrup over the coconut. Stir to combine with a silicone spatula. Press wax paper on top of the mixture and let sit for about an hour so that the syrup saturates the coconut.
Melt and Temper the Chocolate
Cut 18 to 20 ounces of chocolate into small, uniform pieces and put into the glass bowl or measuring cup.
Microwave on 50% for 60 seconds. Stir and put back in microwave.
Continue to cook on 50% in 15 second increments. Take out and stir each time. You do not want the chocolate to melt completely in the microwave. There should be a few lumps that will melt during the final stir.
Add a few chunks of unmelted chocolate and stir for a minute or two. Remove the unmelted lumps and set them aside. They can be remelted and used again.
Repeat for the other chocolate flavor.
Fill the Molds
(Tip: Work with one flavor of chocolate at a time. Finish the eggs, then start on the next flavor of chocolate.)
Pour the chocolate into each egg shape, about ¾ full. Once you have filled one mold, gently tilt and rotate it so that chocolate goes to the top of each egg.
Over a clean sheet of wax paper, invert the mold holding it about an inch above the surface. The excess chocolate will drizzle out on the the wax paper. Hold this position for a minute or two, tilting as necessary.
Turn the mold back over and allow it to sit while you repeat with two other molds. As the chocolate sets up, use the small angled spatula to scrape any excess chocolate off the molds. Set aside these scrapings as they can be remelted and used for the final topping.
Allow the chocolate on the wax paper to cool, then scrape it off and put it back in the bowl. It can be remelted and used again.
Add the Fillings and Finish the Eggs
(Note: You'll have one mold of each filling flavor.)
Add about 1 rounded teaspoon of coconut filling to one mold of eggs. Top with final layer of chocolate.
Prep plastic bags with #12 tips and couplers.
Add 1 cup of arequipe to a bag with the #12 tip. Take another mold and pipe about 1 teaspoon into each egg.
Add 1 cup of peanut butter filling to the other bag with the #12 tip. Take the third mold and pipe about 1 teaspoon into each egg.
Using a soup spoon, pour a little chocolate on top of each egg and spread chocolate around gently to seal. Finish all three molds.
Put the eggs into the freezer for 10 to 15 minutes.
Remove and invert over a tea towel, holding it close to the surface. You can work the molds like an ice cube tray, twisting so that the eggs come out easily. Use a soup spoon to move the eggs to a plate. Avoid touching the eggs with your fingers because you'll leave fingerprints on the chocolate.
Decorate the eggs with drizzles of the other flavor of chocolate. Remelt the chocolate as necessary. It drizzles easier when full melted. Get some chocolate on the end of a knife and drizzle over the eggs in a zigzag motion, or in the design of your choice.