I am making a jungle themed cake for sept 8 in which i will be sculpting animal figures for the first time from fondant. How soon can I begin making them and how should they be stored until I use them? Also, what is the best medium to use fondant or gumpaste? Thank you for any replies in advance.

I like to use a combo of gumpaste and fondant. Since you are doing them well in advance that would be the way I would do it. I like to do them weeks in advance if I can. I usually just store them on a cookie sheet covered in wax paper on my shelf in my pantry closet till they dry completely then I store them in a container with a lid. Keep them out of the sun, they will fade.

I agree with what she ^^^ said
There is a small chance that some of the bigger pieces might develope cracks if too much gumpaste is used. About 50/50 is good but you don't have to be exact

Thank you to all for the great responses. This really helps me a lot!