I'm making a single layer chocolate cake with 7 minute frosting for a Back to School event.  I want to make a yellow school bus out of fondant and place it on the cake with a funny, sorta saying on it.  I'm thinking Back to Skool with the k's reversed written on the bus with gel food coloring.  My question is how will the fondant react with the 7 minute frosting?  This is for kids, and they'll get a sugar high from the cake I think, not my problem.  Thanks in advance for any tips.

Bumping up  

Personally, I would not use 7 minute frosting underneath fondant, although I love to eat it.  I've never done it, but it seems too soft and sticky to be a good choice.  A regular American or Swiss Meringue buttercream would likely be a better choice.