What you cannot do is copy a Lic. Character for profit. That is a NO-NO..even coloring books are protected.
You can "adapt" an idea though. No matter HOW hard you try, your cake will NEVER be the same as the person that originated the design.
When someone brings in a picture of a cake they've seen in a magazine, I always tell them "If that's the exact cake you want, you need to contact the person that made that cake. I can only INTERPRET the work."
It protects me from dissapointing my client. No matter how hard I try, my eyes and hands will NEVER be the eyes and hands of the person who's cake is in the picture.
I'm sorry to say that in this day and age with people being so sue happy, you MUST protect yourself and if you are working from your home, you have to be EVER vigilant or you run the risk EVERYTHING!