Would fondont stick direct to the rice krispie model i made or will i need to put a layer of buttercream on first? Or any other suggestions

Yes, the fondant will stick to the Rice Krispy Treats, but it may not be smooth enough for you.  If not, press the fondant into the RKT's and smooth as much as possible, then add a second layer of fondant for a nice, smooth effect.

yes and also you can use your zester to smooth off the rkt -- if the design will allow

What a great idea, -K8memphis!  I would never have thought of such a thing as smoothing the RKT's with the micro plainer or zester!  If I need a really smooth foundation, I put the Rice Krispies in the food processor and break them down to about one fourth of their original size.  It also makes for a more compact mixture.