I guess it would be worth a shot! By the way - too cute!
The Black and White cake in my avatar was my daughters 30th bday cake. For an additional keepsake gift to her I shadow boxed the sugar pieces for her and they are in the same condition now as they were 6 months ago when i made them. I made sure the shadow box was sealed airtight as possible by using a hot glue gun. From what I understand keeping them stored in an airtight container is the best method of preservation.
You can view the shadow boxed pieces in my photos here,
Hope this helps
If you can get a hold of some of those silica gel packs that come in shoe boxes and purses that will help keep the moisture out.
I was wondering the same thing. I made a jungle cake for my son's first birthday and wanted to keep the fondant/gumpaste animals to put in his room.
I have a couple of fondant figures in my china cabinet and they are a couple of years old. No problems with that. They don't sit in the direct sunlight, which helps keep them from fading.