I need to make a birthday cake for work in a couple of weeks. I am going to do a 2 layer 8" cake to feed 20 people.

Would I be able to cover the cake in chocolate ganache and add fondant flower cutouts as decorations? Will the fondant stick to the ganache and if so do I use more ganache to attach the fondant?

If I end up covering the cake in buttercream instead of ganache how do I best stick the fondant decos to the BC? Can I use additional BC and can the decorating be done the night before?

Thanks