Bettercream/Pastry Pride/Rich's and all other whipped toppings will not work with fondant. Believe me, I speak from experience.
There is too much moisture in the topping and once it comes in contact with the fondant it becomes a gooey drippy mess. If the fondant does not slide off the cake, it will most definitely drip and puddle at the bottom.
I frost all my cakes with Pastry Pride. Once I cut out polka dots out of fondant and put them on the frosted cake. Within less than 30 minutes they slid off and left a colored, sticky trail. They melted off.
However, I have had success with adding fondant and gumpaste (which will also melt) accents by thinly coating the back of the decoration with melted chocolate. If you look at my gallery and see a cake with fondant/gumpaste accents, they were definitely coated with melted chocolate and then placed on the cake.