Hi Phey! I work exclusively with Buttercream, and I cannot recommend any type of Buttercream that could stand up to those temperatures, I would doubt you would do much better with ganache. I would suggest that you could use any form of Buttercream, but you will need to keep it refrigerated until serving. With temperatures that high, I would expect you would have food spoilage if it was left out, regardless of medium! I hope that helps :)
