AHi was wondering if anyone can tell me...I want to mould a wizards hat out of rice krispies can I cover it in icing after. Thankyou

yup!  several people cover rice cereal treats with buttercream to smooth it out before covering in fondant.  i've covered rice cereal treats with royal icing and gumpaste (for extra strong, not-intended-to-be-eaten pieces).

I've covered them with chocolate melts and then fondant :)

I use a layer of buttercream to smooth out my RKT before covering in fondant. I usually smooth some on to fill in the cracks, let that dry, then smooth on a 2nd coat.

Works great!

AI want to make "70" for the top of a cake. Was thinking of making the numbers out of rice crispy treats, then covering with buttercream. Then cover completely with M & M's. thought of using cake pop sticks to mount on top of cake. Will my ideas work? Does anybody have suggestions or better ways of accomplishing this? Thanks

I almost always cover my rice krispies with buttercream first, let it harden up a bit, then cover in marshmallow fondant.

As for the numbers, i usually shape them out of gumpaste (or fondant if I have several days for it to dry), then drive a little wooden skewer through them to give it more structure and so I can stick the other end into the cake. I hope that helps :)