What is a stable frosting for a cake that will be in warm temperatures at an outside party? I'm hosting a party for my son who's turning three at a park. We'll be under cover but not air conditioned - and we're in the middle of a hot Texas summer. The party is early in the day so it's likely to only be around 80-85 Fahrenheit. Still not an ideal temperature for my go-to, a simple American buttercream. 

Is there a frosting type that will keep looking good on cupcakes and be stable for assembling a small two-layer cake at this temperature for the two hours of the party? It's also the only part of the cake my son is likely to eat, so it should taste good and I'd prefer to avoid shortening-based frosting.  

I'd read that Italian buttercream does well at warmer temperatures but it's also got uncooked egg whites, which isn't great sitting outside for a while and with kids (2-3 years old), I'm hesitant to use it.
Here is an interesting entry from King Arthur Flour, who should not have a major stake in the game.  They hit a bunch of varieties with a hair drier to see how they held up.  Their test though was only on holding up to the heat, not safety though.  One could suggest using pasteurized eggs as an option though to get around safety concerns.

Quick summary, they liked Italian Buttercream among the buttercreams they tested.  Shortening over butter helps, but I am in the group who really dislikes the taste of "buttercream" made with shortening over butter, but would go by taste on that.  Of the ones they tested though, cream cheese frosting held up the best, so if the cake is one that would match with cream cheese it might be a good choice.

Fondant is another option which may hold up well to heat though personally, I find it for looks only, not taste.