AHi there... Ok.. So I think I didn't wait long enough for my cakes to cool and when I took them out of the pans the cakes broke - both along the edges... If I use frosting to "glue" the cake together will it collapse under the fondant???? Any suggestions??? Thank you!!

AI would use a stiff buttercream and no soft, liquidy fillings like fresh fruits or jam so that the broken cakes on top will not "slide" out of place. And ice the cake with ganache so that it will for sure keep the cakes intact..That's just me though :)

AI don't think I have enough time to do a ganache since the cake is due early tomorrow morning.. So a stiff buttercream icing as glue for the broken pieces or all around the cake once I glue it together?? Thanks for your help....

..........stiff buttercream icing as glue for the broken pieces or all around the cake once I glue it together??............

Yes, *both*.   You don't want the icing to be too stiff but then it can't be too thin either.