M.M.
As far as I know fondant should only be served or made at room temperature. If you refridgerate it and then take it out for serving later it will sweat and then become unmanageable because of the moisture and lose it's shape. Freezing it is not recommended either.
You can make it in advance and store it in an airtight container. I have made homemade marshmellow fondant and it tastes a lot better than the storebought stuff from Michaels. For bright colors I used wilton candy to melt/mix in with it.
I have not used edible dough or clay. Someone else may have more feedback on that.
HTH!