AI am making a pretty simple cake for my granddaughters first birthday. The design is Polk a dots on one layer and minnie mouse heads and bows on the other. My question is what type of fondant holds up best in heat as party is outside in June. I was a contemplating fonderiffic but not sure if shaped will adhere to the fondant in heat. Any suggestions?

We use our own marshmallow fondant unless it's red, black or brown.  Wilton's brown is pretty yummy (tastes like chocolate fudge brownies), red and black, well, you can take your pick.  All are about the same.  Only reason we don't use what we make on them is it takes so much coloring gel to get the color 'right' that it tastes bad and makes the guests have red or black tongues and teeth.  Making your own is easy and you can get any color you want.  Heat won't affect the fondant so much as the buttercream under the fondant.  Cream cheese can definitely be challenging in a hot environment, and we always caution our customers about going with cream cheese in that setting (as in, we can do it, but we won't be responsible if your cake 'slumps' because your venue is too warm).

AUse gumpaste for the ears, bows and other cake decorations so they will hold their shape and won't droop. Also pink fondant sometimes fades under direct sunlight. My pink tinted homemade MMF did, i don't know about store bought fondant.