I'm covering a chocolate cake in rolled fondant. I've never used rolled
fondant before. From what I understand, a thin layer of buttercream icing
is generally used to smooth the cake surface and help the fondant stick. No
problem.

But I also want to use a layer of raspberry filling and possibly glaze the
cake in raspberry flavour. Can/should I do this under the buttercream or is
the glaze itself sufficient?

I'm also kind of concerned about putting a light colour fondant over top of
a dark cake. A glaze wouldn't help block the dark colour, but buttercream
would.

Is there anyone with cake experience who can provide some guidance on this?