I’m not Hector, but I do love coconut. I don’t know what would happen if you used coconut milk (or water?) in place of the water in rolled fondant. If I were going to try this, I would make maybe 1/4 recipe and try it. The most expensive ingredient is probably the coconut. Make it, see how it handles and tastes, cover a cupcake and see how it drapes.
I don’t have much experience with fresh coconuts, but Cook’s Illustrated did a coconut cake in 2001 that was to die for. I mean, seriously wonderful stuff. It had cream of coconut in the cake and in the buttercream frosting. The one thing that they introduced me to was the coconut extract from Spices Etc. It is extremely potent and all natural. It packs a whollop of flavor. I bought two bottles last time and kept it in the freezer. It isn’t cheap but it is worth it. http://www.spicesetc.com/product/1034/6.
One more thing. I have seen it pointed out that the clear liquid in coconuts is coconut water, while “coconut milk is made by squeezing the grated flesh of a coconut with some hot water resulting in a rich white liquid that looks very much like cow’s milk.” (http://www.coconut-connections.com/coconut_milk.htm)
Using an extract like that might get you the coconut flavor you are looking for either without using the coconut milk/water, or as an enhancement to what flavor it provided, provided that it doesn’t make the fondant not work correctly.
How about making the cordon rose banana cake, torting and filling with a coconut buttercream, skim coating with same coconut buttercream and then topping with the fondant, just plain vanilla flavored, or with the coconut extract to flavor it? The banana cake is such a departure from the chocolate oblivion truffle torte, you are really just going for the exterior design elements. Anything goes for what lies beneath.
I hope this helps a bit. It sounds wonderful.
Best of luck, let us know how things go.