Oooh you want to speak to 3xMummy, she's a cake pro!!
In the recipes section there is a cake thread which I found really helpful when maling DS's cake and there are lots of q&a's from people which might help. I'm not sure what kind of fondant you want to use but I have an awesome marshmallow fondant recipe I can send you if you go that way. Its so yum and so easy to make

Just PM me if you end up wanting it!
Good luck!!