Those are cute Easter eggs! You can try putting a different color soap into the indents of the patterns, let it start to harden, then pour your main color over it. I have found when trying to make detailed soaps with that method that if I let it cool too much, my detail peels off or comes detached from the main piece of soap after I unmold it. I think it has to be slightly hardened but not cooled to pour another color over top, and make sure the soap you pour isn't too hot or it will melt the patttern. A spray of rubbing alcohol on the pattern before pouring the main color is supposed to help it stick as well.
Soap paints are colors you can pain the soap with after unmolding. I actually just bought some but haven't had a chance to try them out yet. I think there are some folks here who do that, hopefully they will see this post to tell you more about it.