I make mine ahead of time and put it in the fridge, then I don't have to worry about the icing getting warm and loosing it placing if I had put it on the side.
Other things I do too is a just use a ziplock bag and snip the corner inside of buying those costly piping bags. But if you want fancy designs in the frosting you won't have the tips? Anyway, I just just the ziplock. I make own frosting instead of buying. I don't like buttercreme and I also have a picky DH when it comes to frosting.. no lie.
As for as food coloring, use a few drops at a time to get the desired color. I've made some that have way way too much and they have colored mouths.
Good luck and can't wait to see the cake!!
P.S. I love the jungle cup cakes!! Adorable!